How then are we to receive these words of the Lord? "He who receives Me receives Him who sent Me." These words express the unity of nature between the Father and the Son. "He who receives the one whom I shall send receives Me." These words refer to the unity of nature between the Son and His messenger.
There is nothing unfitting in this understanding, since the Word became flesh, that is, God became man. Thus, probably in unity with human nature, He said, "He who receives the one whom I shall send receives Me." But according to the divine nature He said, "He who receives Me receives Him who sent Me."
Yet in this passage He spoke not so much of unity of nature as of the authority of the sender over the one sent. Let everyone receive the one sent, so that in him he may discern the one who sent him.
Therefore, if you seek Christ in Peter, you will find Peter's Master. If you seek the Father in the Son, you will find Him who begot the Only-begotten. Finally, when you receive the one sent, you will not err in believing that you receive also the sender.
Did He really wish us to think that the difference between the one whom He sends and Himself is the same as between Himself and God the Father? If we receive this in that way, then I do not know what steps we must build. May it never be! This would be according to the Arian principle.
Augustine goes on to speak of steps of dignity which, in the Arian view, separate God the Father and God the Son. The word gradus is best understood as "steps," since Augustine uses it to form the image of a ladder. On its different steps the heretics place the Father, the Son, the Holy Spirit, and the Apostles. By it the Arians descend to death rather than ascend to heaven. At the end of the passage he speaks directly of the heretics' ladder, scalae.
When they hear or read these Gospel words, they at once hurry to those steps of their teaching. By them they do not ascend to life, but descend to death. They immediately begin to say, "As far as the Apostle of the Son is from the Son, according to His words, 'He who receives the one whom I shall send receives Me,' so far is the Son from the Father, according to His words, 'He who receives Me receives Him who sent Me.'"
But if you speak so, heretic, you have forgotten your own steps. If, on the basis of these words of the Lord, you define the distance between the Son and the Father as the same as that between the Apostle and the Son, where will you place the Holy Spirit?
Has He vanished from you, whom you usually place after the Son? Then He will stand between the Apostle and the Son. In that case the distance between the Son and the Apostle will be much greater than that between the Father and the Son.
Or perhaps, so that the same distance may remain between the Son and the Apostle and between the Father and the Son, the Holy Spirit will be equal to the Son? But you do not want this. Where then will you place Him, if you establish the same distance between the Apostle and the Son as between the Son and the Father?
Therefore restrain the boldness of your prejudice. Do not try to find in those words the same distance between the Father and the Son as between the Son and the Apostle. Rather hear the Son Himself when He says, "I and the Father are one" (Jn 10:30).
Here the Truth left us no hint of distance between the Begetter and the Only-begotten. Here Christ shattered your steps. Here the Stone broke your ladder.
After refuting the slander of the heretics, how should we receive these words of the Lord: "He who receives the one whom I shall send receives Me; he who receives Me receives Him who sent Me"?
If we wished to understand, "He who receives Me receives Him who sent Me," as an assertion of the one nature of the Father and the Son, then the similar form of the phrase, "He who receives the one whom I shall send receives Me," would seem to assert one nature of the Son and the Apostle.
Indeed, this could be understood in such a way. For the Giant had a twofold nature, He who rejoiced to run His course (cf. Ps 19:5). "The Word became flesh" (Jn 1:14), that is, God became man.
Therefore one may suppose that He said, "He who receives the one whom I shall send receives Me" as man. And "he who receives Me" as God "receives Him who sent Me."
But if He spoke so, He was emphasizing not unity of nature, but the significance of the Sender in the one sent. That is, let each one receive the sent one in such a way as to see in him the Sender.
Thus, if you seek Christ in Peter, you will find the Master of the disciple. If you seek the Father in the Son, you will find the Begetter of the Only-begotten Son. So in the person of the one sent, you will unfailingly receive the Sender.
What follows next in the Gospel need not be pressed into the narrow limits of time. Therefore, beloved, let the words already spoken be well digested by you, like food for holy sheep, if this is enough. If it is not enough, let them be carefully chewed over.