Christ explains His saying. He indicates the active principle and the manner of rebirth: the Holy Spirit, by the power and action of His gracious gifts, through the mediation of water, regenerates man and transforms or re-creates his nature.
This rebirth gives man a new beginning of life. From it a new direction can develop, opposed to that ruling beginning and direction found in every unregenerate man.
Such a man is a member of mankind infected by sin, from which it cannot free itself by its own powers alone.
When and in whom this spiritual rebirth, or transformation, is accomplished, and this new beginning of life appears, then that person can see the Kingdom of God and enter it.
This is the necessary condition without which it is impossible to become a participant in it.
Now Nicodemus could understand more clearly what Jesus required. He knew water as a means of purification prescribed by the law in certain cases, for example, Num 19:7. Of course, he himself used it as a means of purification.
He knew water as a symbol of inner, spiritual cleansing, of which the ancient prophets spoke, for example, Is 1:16.
This water was sometimes used in the reception of proselytes. John the Baptist also used it, preparing the Jews for the Kingdom of the Messiah, binding them to repentance and the confession of their sins.
Nicodemus knew John's baptism of repentance, although perhaps he did not understand it.
Now John had said, and Nicodemus could not fail to know it, that the One coming after him would baptize with the Holy Spirit (Mt 3:11).
The Jews also expected that the Messiah would baptize (Jn 1:25).
Therefore, when Nicodemus heard Jesus Christ speak of birth by water and the Spirit, he should at last have understood that Jesus was speaking to him of the necessity of baptism for participation in the Kingdom of the Messiah.
Without doubt, however, he did not understand this rebirth through baptism. He probably wondered why it was needed for the descendants of Abraham, the direct and first heirs of the Kingdom of the Messiah.
Why this is necessary for all, the Savior reveals in the words: "That which is born of the flesh is flesh, and that which is born of the Spirit is spirit."
First of all, let us note that the Evangelist John uses the expression "that which is born," in the neuter, instead of "he who is born," in the masculine. Compare Jn 3:8 and 1 Jn 5:4.
Likewise, he uses the words "is flesh" and "is spirit" instead of "is fleshly" and "is spiritual."
The whole expression means this: the man born of flesh is fleshly, and the man born of the Spirit is spiritual.
Thus the necessity of rebirth for everyone who wishes to participate in the Kingdom of God is founded on this: every man born of what is fleshly is fleshly.
What does this mean? In the usage of Holy Scripture, the word flesh has several meanings.
Besides the direct meaning of the material part of the human constitution, this word also has the following meanings.
First, flesh means man's sinful sensuality, that is, the sins of the flesh.
It is the distorted condition of bodily needs. Through the action of sin upon them, they have changed their natural purpose.
They are no longer satisfied by what should satisfy them for the life of the spirit. By fastening the will to other objects, they demand another satisfaction.
This is sinful sensuality in its active influence upon the spirit and the moral life.
To express this notion of flesh, the holy Apostle Paul uses such expressions as "the body of the flesh" (Col 2:11), "the body of sin" (Rom 6:6), and "the desire of the flesh" (Eph 2:3; cf. 2 Pet 2:18; Jn 1:13).
Second, the same Apostle calls flesh not only man's sensory sinfulness, but also his spiritual sinfulness.
Thus he includes idolatry, sorcery, dissension, and heresies among the works of the flesh, though these deeds clearly do not belong to sensuality (Gal 5:19-21).
He also calls flesh the hope of some to be justified by works of the law (Gal 3:3; cf. Rom 4:1).
He likewise calls flesh the attachment of the Corinthian Christians to pagan philosophy (1 Cor 1:26).
Finally, third, flesh signifies not only the manifestations of sensory or spiritual sin, but the very principle of sin acting against the principle of good (Gal 5:17).
In general it signifies the whole sinful, ungraced man, living and acting under sin and not according to God (Rom 7:5; Rom 8:1, 4, 8, 9; 2 Cor 10:2; cf. Gen 10:6; Acts 2:17).
In this last meaning the word flesh is used in the present place.
Flesh is the very principle of evil in man. It opposes good, defiles the whole man, and prevents him from being reconciled to God.
It holds him in a state of falling away from God and resisting Him. From it come all particular transgressions and sins.
This is inborn sin, which has infected the whole human race. It is the chief obstacle for everyone to reconciliation with God and entrance into the Kingdom of Christ.
This obstacle must be destroyed, and it is destroyed in rebirth or baptism.
This sin is passed from parents to children. Therefore, he who is born of the flesh is himself flesh.
Thus the Savior's words may be paraphrased in this way.
Every man, insofar as he is born of parents infected with inborn sin, bears this sin upon himself.
Therefore he cannot be a participant in the Kingdom of the Messiah until he is cleansed from this sin in baptism.
He must also be cleansed from the voluntary sins that proceed from it, until he is born from above.
With respect to Nicodemus's notions about the Kingdom of the Messiah, this expression made known to him that all Jews, and he himself, despite their descent from Abraham, are flesh.
Consequently, they too need rebirth in order to participate in the Kingdom of the Messiah, just as those who do not descend from Abraham according to the flesh need it.
That is, by this expression the strange prejudice of the Jews was rejected: that fleshly descent from Abraham alone gives the right to participate in the Kingdom of the Messiah.
On the other hand, if Nicodemus did not understand what sin is, and if he regarded sin only as an external, actual transgression of the law, then he had to learn otherwise from these words of the Savior.
He may have thought that sin could to some degree be cleansed by various external actions, for example by prescribed washings and the like.
Yet from these words he had to learn that sin is not merely this or that particular sinful deed.
Rather, the whole condition of unregenerate and ungraced man is a sinful condition.
Consequently, external actions alone are not enough for cleansing oneself from sin. A complete regeneration is necessary, or rebirth from the Holy Spirit.
For only that which is born of the Spirit is spirit. That is, only the one born of the Holy Spirit is spiritual.
Such must be every true member of the Kingdom of the Messiah, since this Kingdom is spiritual. Therefore all must be born of the Spirit.
It is obvious that in this last saying of the Savior, the word Spirit, used twice, is not used in the same meaning in both places. Otherwise there would be mere reciprocity.
In the words "that which is born of the Spirit," Spirit clearly means the Holy Spirit, or God generally as Spirit.
This expression directly points to the preceding words: "unless one is born of the Spirit."
Here the active cause of rebirth is expressed: the Holy Spirit, or the gracious power of the Holy Spirit.
In the final expression, "is spirit," it is not the active cause that is indicated, but the very essence of rebirth produced by the power and action of the Holy Spirit.
The Holy Spirit sanctifies man by cleansing his sinful defilement.
He re-creates in him the image and likeness of God the Spirit, which sin had distorted.
He grants him the strength to be spiritual, morally perfect, and holy.
The fleshly man cannot be such (1 Cor 2:14). This change is accomplished by the power of the Holy Spirit in rebirth.
Therefore all without exception who wish to participate in the Kingdom of the Messiah, Jews and Greeks, must be reborn of water and the Spirit.
THEOSIS