John 17:3Meaning & Commentary from the Church Fathers

And if the Son is not true God, how is He "the Truth"? Truth differs very little from true.

Tell me, what shall we call a man who is not a true man? Surely not a man at all.

So too, if the Son is not true God, how can He be God? And how can He make us gods and sons, if He Himself is not true?

We have spoken of this more fully elsewhere. Therefore let us go on.

Since in yesterday's discourse something remained unsaid about the words, "that they may know Thee, the only true God, and Jesus Christ whom Thou hast sent," I think it necessary to explain the next thought of the saying.

Regarding the words "the only true God," prophecies and testimonies were brought forward showing that the Son is the only true God. Now we must address the mission of the Son by the Father.

"What then," the heretic will say, "can you say about the Son's being sent by the Father? It is written plainly: 'and Jesus Christ whom Thou hast sent.' Can the sender have the same dignity as the one sent?"

Certainly, if in reading these words you slavishly follow the letter, then, as we have often said before, you will contradict us in many things. You will judge unreasonable what is beautifully written but badly understood.

But if you grasp the thought correctly, then your spiritual eye, guided by the Holy Spirit Himself toward exact understanding, will notice no contradiction anywhere.

Indeed, the words "sent" and "He sent," though human words, express divine thoughts. The One who sent did not send from one place to another. The One sent did not come from one place to another.

But the Father, says the heretic, sent the Son into the world as though He were not in the world to which He was sent.

How then does Scripture say, "He was in the world, and the world was made through Him" (Jn 1:10)? How, then, did the One present come, or the One hidden appear?

If you truly understand "sent" as you hear it, then it is altogether necessary that the One sent appeared in places where He was not yet present. It is also necessary that the Sender sent Him where He Himself was not present.

How then did the Evangelist say, "All things were made through Him, and without Him nothing was made that was made. He was in the world, and the world was made through Him" (Jn 1:3, 10)?

If He was in the world, how is He sent into the world? Have you not heard Him say, "Do I not fill heaven and earth? says the Lord" (Jer 23:24)?

What then does "sent" mean? It means: He appeared. It means: He shone forth according to the flesh.

Mission does not indicate a passage from place to place. It indicates a passage from the state of invisible Godhead into visible presence.

Truly, when the Son of God came to earth and assumed human nature according to the divine economy, He did not deprive heaven of His majesty. And now, having ascended in the flesh, He has not left the earth bereft of His governance.

Let us explain the question in another way. If, brothers, the Father literally sent the Son into the world, it is clear that the Sender is separated from the Sent in His place of abiding.

If the Sent is with the Father, then "He sent" is needless. But if the Father sent, then according to the expression He is separate.

We must not be enslaved to the letter. We must walk by faith.

Who, then, will assure us that the Son of God, having appeared on earth, was in heaven? What word will certify that the One sent by the Father was not separated from the Father?

If He is sent into the world according to the letter of the saying, and if the Sender is separated from the Sent, how does Christ say, "I am in the Father and the Father in Me" (Jn 14:11)?

Again, how did He say, "I am not alone, but I and the Father who sent Me," and, "He who sent Me is with Me" (Jn 8:16, 29)?

Do you see that the nature is not divided, while the divine economy of the Incarnation merely shows the form of mission?

Again, what does "I ascend to My Father" mean (Jn 20:17)? If the Father abides with Him, why does He ascend?

The ascent signifies the divine economy, the ascension of the body, not a separation from the Godhead.

Do you wish to know that the Son of God, when He came to earth, did not leave heaven or separate from the Father? And that when He ascended into heaven, He did not abandon the earth?

After saying to His disciples, "I ascend" there from where I descended, "to My Father," He Himself again says to them, "I am with you always, to the end of the age" (Mt 28:20).

Therefore the words, "that they may know Thee, the only true God, and Jesus Christ whom Thou hast sent," contain a twofold thought and present a two-edged sword.

One edge is directed against idolatry, the other against Jewish unbelief. They point to the one true God in order to put dead idols to shame.

They point to Jesus Christ who was sent, in order to close the mouths of those who deny the Incarnation.

Therefore understand these words in the sense indicated, and do not offend the divine majesty for the sake of the letter.

So that you may fully know that mission from God does not mean movement from place to place, but indicates the Incarnation, I will point out the following.

Of John the Baptist, who was from the earth and appeared on the earth, the Gospel says, "There was a man sent from God" (Jn 1:6).

Was John sent from heaven? Did he come from the heavenly height? How then did he come?

If a man who is sent did not pass from one place to another, but was sent in the sense that a certain ministry was entrusted to him, then what of God the Word, who fills all things?

Does He abase His nature, rather than indicate the divine economy, when He calls Himself sent?

Likewise, in the words, “the glory that comes from the only God you do not seek,” Jn 5:44, the heretics’ understanding would yield this conclusion: since the Father is the only God, the Son is not God at all. But such a conclusion is truly madness.

Therefore He calls God the Father "the only" and "true" God, setting Him as true over against those falsely named and falsely called gods. This is the meaning of the saying.

Yet while calling the Father the only and true God, He beneficially mentions His own glory also, saying, "and Jesus Christ whom Thou hast sent."

No one can receive perfect knowledge of the Father unless, alongside it and together with it, there is also knowledge of the Son. For whoever has known that there is a Father has certainly known the Son together with Him.

Therefore, by calling God and the Father true, He did not exclude Himself. Since He is in Him and from Him by nature, He too will be true and one in the One.

Apart from Him there can be no other true and only God, "for the gods of the nations are demons" (Ps 95:5). Creation is a servant, though some worship it for no reason I know, having been carried away into an evil and irrational disposition.

Thus the one and true God is set against the many who, through error, have been acknowledged in the world as gods and have received a counterfeit name.

Together with Him is the Son, who is in Him and from Him by nature, distinct and yet united according to natural unity.

Distinct, because He is understood to have existence in Himself, for He is Son and not Father. Yet also united, because the One born from the Father by nature must certainly accompany the Father's existence.

The Father and the Son exist together. If the Father exists and is named, it is surely because He is understood as having begotten.

Therefore He says, "This is eternal life, that they may know Thee, the only true God, and Jesus Christ whom Thou hast sent."

But will one of the studious ask whether we must recognize knowledge as eternal life? Will it be enough to know that God exists truly and actually by nature, in order to possess the whole firmness of hope?

Will nothing else be required? In that case, how is it that "faith without works is dead" (Jas 2:26)?

When we name faith, we indicate true knowledge of God, and no other kind, for knowledge comes through faith. Isaiah testified to this when he said, "If you do not believe, neither will you understand" (Is 7:9).

That knowledge made up only of bare notions is declared by the writings of the saints to be altogether useless, I think you may understand from the following.

One of the holy disciples said, "You believe that God is one. You do well. Even the demons believe, and tremble" (Jas 2:19).

What then shall we say to this? How will Christ be true when He calls the knowledge of the only and true Father and God, and of the Son with Him, eternal life?

To this, I think, we must answer that the Savior's word must certainly be true. Knowledge is life, as it brings forth the whole power of the mystery and introduces participation in the mystical Eucharist.

Through it we enter into communion with the living and Life-giving Word. For this reason, I think, Paul calls the Gentiles members of the same body and partakers of Christ (Eph 3:6), since they partake of His holy Flesh and Blood.

In the same way, our members must be understood as members of Christ (1 Cor 6:15). Therefore knowledge is life, also bringing blessing through the Spirit.

He dwells in our hearts, transforming those who receive Him unto adoption and recreating them unto incorruption and piety through the evangelical life.

Therefore our Lord Jesus Christ, knowing that the knowledge of the one and true God is the cause and pledge of these blessings, says that it is eternal life.

It is the mother and nurse of eternal life, as though by its own power and nature it brings forth what causes life and leads to it.

We must, I think, direct our inquiry also to this: how, according to Christ's word, the most perfect knowledge of the one and true God arises in us.

Observe that it does not occur without knowledge of the Son, and certainly of the Holy Spirit. For in this way the Unity in Trinity is understood and believed according to the Scriptures.

The Jews, guided by the commandments of Moses away from many falsely named gods, were drawn to the service of the One and True God. For the law says, "You shall worship the Lord your God and Him only shall you serve" (Deut 6:13; Mt 4:10).

Yet those who were serving and already worshiping the One and True God did not yet have perfect knowledge of the One worshiped. Now, through the words of our Savior, they are called to this knowledge.

They are taught not only that the Creator of all is one and true, but also that He is Father, and whom He has begotten. Indeed, they now behold Him precisely in the unchanging Image, that is, the Son.

Through the imprint, everyone can very easily come to exact contemplation of the prototypes.

Therefore our Lord Jesus Christ considers it necessary that those called through faith to sonship and eternal life should know not only that God is one and true.

They must also know that He is Father, and whose Father He is. He is clearly the Father of Him who for our sake became flesh and was sent to correct the corrupted rational nature, that is, mankind.

If, in contrast to the falsely named gods of the Gentiles, the Father is the only true God, united, of course, with the Son by identity of nature, then let those who call Him a creature consider this.

Do they not pass beyond every boundary of impiety when they say that He is created, though to Him truly belongs being God together with the One who begot Him?

"This is eternal life, that they may know Thee, the only true God, and Jesus Christ whom Thou hast sent." When our faith becomes truth through vision, then eternity will receive our mortality once it has been changed.

What He said to His servant Moses, "I am He Who Is" (Ex 3:14), we shall behold when we live in eternity.

Leaving the Arians aside, we must consider whether we are compelled to understand the words addressed to the Father, "that they may know Thee, the only true God," as though He wished to tell us that only the Father is true God.

Rather, we should receive no one as God except the Trinity: Father, Son, and Holy Spirit.

Shall we not, on the testimony of the Lord Himself, call the Father the only true God, the Son the only true God, and the Holy Spirit the only true God?

And shall we not also call the Father, Son, and Holy Spirit together, that is, the whole Trinity, one true God, not three true gods?

Or does "the only true God" also refer to the added words, "and Jesus Christ whom Thou hast sent," so that the order is this: "that they may know Thee, and Jesus Christ whom Thou hast sent, as the only true God"?

Why then did He not mention the Holy Spirit? Is it not because when one is named who is connected with another in such unity that through this bond two become one, this very bond must be understood, even if it is not mentioned?

"And this is eternal life," He says, "that they may know Thee, the only true God, and Jesus Christ whom Thou hast sent."

The order of the words should be this: "That they may know Thee and Jesus Christ whom Thou hast sent as the one true God."

Accordingly, the Holy Spirit is also implied here, for He is the Spirit of the Father and the Son, as it were the substantial and consubstantial love of both, tamquam caritas substantialis et consubstantialis amborum.

For the Father and the Son are not two Gods, nor are the Father, Son, and Holy Spirit three Gods. Rather, the Trinity itself is the one and only true God.

And yet the Father is not the Son, the Son is not the Father, and the Holy Spirit is not the Father and the Son. For Father, Son, and Holy Spirit are three Persons, but the Trinity itself is one God.

If, then, the Son glorifies Thee in this way, as Thou hast given Him authority over all flesh, and hast given it so that He should give eternal life to all whom Thou hast given Him, this follows.

And if "this is eternal life" (Jn 17:2-3), that they may know Thee, then the Son will glorify Thee by enabling all whom Thou hast given Him to know Thee.

Likewise, if the knowledge of God is eternal life, then the more we advance in this knowledge, the nearer we draw to that life.

In eternal life we shall not die. Therefore the knowledge of God will be perfect when there is no death.

Then there will be the universal manifestation, clarificatio, of God, because the highest glory will come. In Greek this is δόξα, from which δόξασον is formed, meaning "glorify."

Some translate this into Latin as clarifica, "make known," and some as glorifica, "glorify."

Among the ancients, however, "glory," gloria, by which men are called "glorious," gloriosi, is defined in this way: "Glory is widespread report about someone, containing praise."

But if a man deserves praise when report about him is believed, what praise will God receive when He is seen?

Therefore it is written: "Blessed are those who dwell in Thy house; they will praise Thee continually" (Ps 83:5).

There will be endless glorification of God where there will be full knowledge of God. And because the knowledge will be full, the manifestation or glorification will also be supreme.

Thus also in Deuteronomy it says, “The Lord alone led them, and there was no strange god with them,” Deut 32:12. If God alone is invisible and wise, it does not follow from this that He is in every respect greater than all. Yet God over all necessarily surpasses all. Did the Apostle, when he said that the Savior is “God over all,” Rom 9:5, name Him greater than the Father? This would be absurd. Therefore this present passage must be understood in the same way. The great God cannot be less than another God. Did the Apostle, when he said of the Son, “we await the blessed hope and the appearing of the glory of our great God and Savior Jesus Christ,” Tit 2:13, consider Him greater than the Father? For we await the appearing and coming of the Son, not of the Father. Therefore this is said without dividing Father and Son, and not with strict precision. To be equal with God means nothing other than to be equal to God. How then is the Son, who did not consider it robbery to be equal with God, Phil 2:6, unlike and unequal to God? But the Jews are more pious than Eunomius. For when the Savior merely called Himself the Son of God, since the Son, if He is truly Son, must be equal to the Father, they wanted, as it is said, to stone Him. This was “because He not only broke the Sabbath, but also called God His own Father, making Himself equal with God,” Jn 5:18. Therefore the Son is equal to the Father both according to the Apostle’s testimony and according to the word of the Savior Himself, even if Eunomius does not wish it.

If perfection is lacking in goodness, power, wisdom, time, or place, then there will not be God. Identity in all things points rather to one God, not many. Moreover, if there were many gods, how would their indescribability be preserved? For where one was, another would not be. How would the world be governed by many, and would it not be destroyed and thrown into disorder when war arose among those who governed? If someone says that each governs his own part, then what introduced this order and made the division among them? That one would properly be God. Therefore God is one: perfect, indescribable, Creator of all, Sustainer and Ruler, above and before every perfection. To this one must add that, by natural necessity itself, the unit is the principle of the dyad.

Since those inherit eternal life who know the one true God and Jesus Christ whom He has sent, it is evident that through the salvation of believers both the Father and the Son are glorified. Thus the whole connection in the meaning of the Lord’s words is this: Glorify Thy Son, that Thy Son also may glorify Thee, as Thou hast glorified Him and wast glorified by Him when Thou gavest Him authority over every flesh, Jn 17:1-2, and He gave eternal life to believers. See also how He taught the unity of the Godhead by saying, “that they may know Thee, the only true God.” To this He also added the dogma of His saving Incarnation: “and Jesus Christ whom Thou hast sent.” He did not say. “the Word whom Thou hast sent,” lest anyone, taking occasion from this, should think that He separates and divides His Godhead from the Godhead of the Father. Instead He said, “Jesus Christ whom Thou hast sent,” so that everyone may understand that He is speaking about His becoming man. From this He distinguishes only the Godhead from His humanity, utterly uprooting polytheism. He says: Let them know and believe in the one true God alone and in the incarnate Christ. Not in two gods, but in the one Godhead alone of the Father, the Son, and the Holy Spirit, although the Son became incarnate and became man. What He said in prayer, He again explains in the words that follow.

Conversely, the importance of accepting the truth revealed by God is shown by this. Even in the Old Testament the Lord Himself reproached the people of Israel through the prophet (Jer 2:13).

He reproached them because they had forsaken Him, the Fountain of living water, and had dug for themselves broken cisterns that could hold no water.

In other words, Israel sought false sources of the knowledge of God and piety. By them it wished to satisfy the thirst of its search for truth.

But instead of satisfying that thirst, it inflamed it more and more. Such was Israel's condition in the days of the coming of Jesus Christ.

Israel had given itself over to falsehood, become a slave of passions and sins, and sought truth in the traditions of the elders and human inventions, not in the word of truth.

For this reason it was dead and barren. It had become permeated with falsehood, so that the Savior called the Jews sons of the father of lies, the devil, and slaves of sin.

Now He brought truth to earth, which was to set them free. He Himself, as Son of the living God and as Truth, was to free them from this slavery to falsehood and sin.

He was to give them the fountain of life, and He truly gave both truth and the water of life. His disciples were the first to drink of that water and the first to understand the truth.

He prays that they may be preserved for men, for life, and for truth.

The final words of the high-priestly prayer are: "that Our love may be in them." This is that life-giving fountain which flows from God and gives life to human hearts.

Instead of the withering egoism that separates men from God and divides them from one another, it brings a close bond among them. It binds them into one, gives life, and removes every falsehood and hypocrisy from human relations.

Love brings life, truth, and light into human relations. It leads them to God, the Fountain of Life, Light, and every good.

Jesus Christ pronounces His high-priestly prayer aloud before all the disciples for this purpose: that all may know how and for what the Son of God prayed in the last moments of His earthly life.

They were also to know how He regarded the work of man's salvation that He had accomplished.

According to blessed Augustine, "With such a Teacher, not only His discourse with the disciples edifies them, but also His prayer for them. If it edified those who heard the words of the prayer then, it certainly edifies us who read what was written."

By His high-priestly prayer, Jesus Christ concludes the last supper with the disciples and the discourse of love. He then goes forth to the labor of self-denial and love for the whole human race.

A few more hours of His presence with them will show how their Teacher emptied Himself unto death on the Cross, for love of the human race and for our salvation.

Then He will ascend to His Father, to prepare a place for them and for us.

“And Jesus Christ,” that is, as the Redeemer of the world. Such knowledge embraces the whole essence of Christian knowledge in its content. For by such knowledge, which is inseparable from faith, the one who knows or believes appropriates the redemptive merits of the Savior as the true envoy of the one true God. Therefore such knowledge is eternal life, for it places man in spiritual union with the source of eternal life, God and Christ. Compare the notes on Jn 3:14-16.

This is the same true God by whom Jesus Christ was sent, though He was rejected by the Jews. The ancient world had to abandon two errors. One was paganism, which did not know the true God. The other was corrupted Judaism, which was carried away by dreams of an earthly kingdom of the Messiah and refused to receive the Messiah in the person of Jesus Christ, Jn 5:37-38; Jn 8:42-43, 54-55. The world must always keep two errors in view as most destructive for it, since they deprive it of eternal life. One is the deification of creation, which renounces faith in the personal existence of God. The other is the denial of the need for a Savior for sinful humanity. “This is His commandment, that we should believe in the name of His Son Jesus Christ,” 1 Jn 3:23. “That they may know Thee... and Him whom Thou hast sent.” These words of Christ Jesus contain not the slightest contradiction of His divine dignity. Neither do His earlier words: “Believe in God, and believe in Me,” Jn 14:1. He takes away the glory of the Godhead from the false gods invented by mankind. Of Himself He speaks only as the Messiah. This is His essential thought. If anyone wishes to know His eternal properties, he can learn them from this very prayer. Here He calls Himself the Son of God, verse 1. He ascribes to Himself existence before the world, verse 5. He speaks of His equality with God the Father, verses 1, 21, 22. “That they may know Thee.” “By knowledge,” says Saint Cyril, “He means not simple knowledge of God, but faith revealed in good works.” This is a true observation. In the language of holy Scripture, knowledge does not mean only an act of thought. It includes an act of the mind with corresponding dispositions of the whole soul, or the reception of truth by the whole soul. “If anyone thinks that he knows anything, he does not yet know as he ought to know. But if anyone loves God, he is known by Him,” 1 Cor 8:2-3. Thus Saint Paul teaches, and thus all holy Scripture teaches, Gal 4:9; 1 Jn 4:1. Applying living knowledge to the great objects of knowledge indicated in the Lord’s instruction, we find that living knowledge of God is the same as repentance before the true God. Living knowledge of Christ Jesus is love for the Lord Jesus. From this it is also clear why the Lord Jesus points to eternal life in the knowledge of God and Christ Jesus.