John Chrysostom
What I have said many times, I will say now also, and I will not cease saying it. What is it? That when Jesus intends to touch on lofty doctrines, He often adapts Himself to the weakness of His hearers. He uses a form of teaching not always corresponding to His majesty, but rather adapted to them.
Lofty and important teaching, once expressed, can sufficiently show its dignity insofar as we are able to hear it. Yet if He does not often speak about matters simpler and nearer to the understanding of His hearers, then lofty matters cannot quickly take possession of a mind bent downward.
Read more (403 words)
For this reason Christ spoke much more about simple matters than lofty ones. But so that this would not cause harm in another respect, that is, so that it would not keep the disciple below, He turns to simple matters only after first stating the reason why He speaks of them.
He did this in the present case. After speaking of baptism and the birth accomplished on earth by grace, He then intended to proceed to speak of His own birth, ineffable and incomprehensible. Yet for the moment He delays and does not proceed. Then He states the reason why He does not proceed.
What reason is this? The coarseness and weakness of His hearers. He was hinting at this when He said, "If I have told you earthly things, and you do not believe, how will you believe if I tell you heavenly things?"
Thus, wherever He says something simple and humble, it must be referred to the weakness of the hearers.
Some say that the expression "earthly things" here must be understood of the wind, as though He said: I showed you an example from earthly things, but you are not persuaded even by this. How, then, can you understand more exalted matters?
But if He here also calls baptism earthly, do not marvel. He calls it so either because it is accomplished on earth, or in comparison with His dread birth. Our birth in baptism, though heavenly, is earthly in comparison with His true birth from the Essence of the Father.
It is just that He did not say, "You do not understand," but, "You do not believe." Whoever is troubled by something intelligible to the mind and does not readily accept it may rightly be accused of lack of understanding. But whoever does not accept what cannot be grasped by reason, but only by faith, deserves accusation not of lack of understanding, but of unbelief.
Thus, by not allowing Nicodemus to test with his mind what had been said, Christ continues still more strongly to convict him of unbelief. If our spiritual birth must be received by faith, what do those deserve who scrutinize with their mind the birth of the Only-begotten?
But perhaps someone will say: why speak of this if the hearers did not wish to believe? Because although they did not wish to believe, people of later times could receive it and gain benefit from it.