A Homily by St John Chrysostom on John Chapter 3.

Nicodemus, as yet, could think of Christ only as human. and therefore he greeted Christ as a Prophet, for on this wise he was fain to account for Christ's power of working miracles. What then saith Christ? He saith: Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God. That is to say: If thou partake not of the Spirit from the Laver of Regeneration, thou canst not make a right estimate of me, for the estimate which thou hast made is not spiritual, but carnal. It is impossible, saith Christ, for one not so born to see the kingdom of God; and by this word See, he would shew that we need other than natural sight if we would perceive what Christ is. Having heard this, Nicodemus saith: How can a man be born again when he is old? And thus do hereticks continue in their heresy, saying: How as Christ begotten? And thus do they attempt to comprehend Infinite Being within the limitations of their own reasoning.

Can a man, saith Nicodemus, enter the womb, and be born? Seest thou how, when a man committeth spiritual things to his own reasonings, he speaketh ridiculously? Nicodemus hath but just now heard of spiritual generation in Baptism, yet he perceiveth it not as a spiritual matter, but interpreteth the words of Christ in a gross physical sense. Of such Paul said: The natural man receiveth not the things of the Spirit. Yet in all this Nicodemus evidently preserved his reverence for Christ, even though he was astonished in mind. Let us therefore thing reverently. We have heard that the Father begat the Son; let us believe, and let us not ask, How?

Except, saith Christ, a man be born of water and of the Spirit, he cannot enter into the kingdom of God. Yet even this, Nicodemus did not understand. Nothing is worse than to commit spiritual things unto argument. This is why we are called The Faithful, namely, because we do leave human reasonings below as we ascend the heights of the Faith. At the first creation, God made man in his own image, but in the new creation God actually uniteth man to himself. Therefore, let us believe what God hath said [when he that baptizeth speaketh for God, in the Name of God, saying: The servant of God is baptized in the Name of the Father, and of the Son, and of the Holy Ghost] and let us answer, Yea, verily, amen. For the power of the Father, and of the Son, and of the Holy Ghost, fulfilleth these things; through the grace and loving-kindness of the same our Lord Jesus Christ, to whom with the same Father, and the same Spirit, be glory for ever and ever. Amen.