How can these things be? We see what is the chief obstacle in the way of Nicodemus. Every thing that he hears appears monstrous, because he does not understand the manner of it; so that there is no greater obstacle to us than our own pride; that is, we always wish to be wise beyond what is proper, and therefore we reject with diabolical pride every thing that is not explained to our reason; as if it were proper to limit the infinite power of God to our poor capacity. We are, indeed, permitted, to a certain extent, to inquire into the manner and reason of the works of God, provided that we do so with sobriety and reverence; but Nicodemus rejects it as a fable, on this ground, that he does not believe it to be possible. On this subject we shall treat more fully under the Sixth Chapter.

How can these things be? - Nicodemus was still unwilling to admit the doctrine unless he understood it; and we have here an instance of a man of rank stumbling at one of the plainest doctrines of religion, and unwilling to admit a truth because he could not understand "how" it could be, when he daily admitted the truth of facts in other things which he could as little comprehend. And we may learn:
1. that people will often admit facts on other subjects, and be greatly perplexed by similar facts in religion.
2. that no small part of people's difficulties are because they cannot understand how or why a thing is.
3. that people of rank and learning are as likely to be perplexed by these things as those in the obscurest and humblest walks of life.
4. that this is one reason why such men, particularly, so often reject the truths of the gospel.
5. that this is a very unwise treatment of truth, and a way which they do not apply to other things.
If the wind cools and refreshes me in summer if it prostrates the oak or lashes the sea into foam - if it destroys my house or my grain, it matters little how it does this; and so of the Spirit. If it renews my heart, humbles my pride, subdues my sin, and comforts my soul, it is a matter of little importance how it does all this. Sufficient for me is it to know that it is done, and to taste the blessings which flow from the renewing. and sanctifying grace of God.

How can these things be? - Our Lord had very plainly told him how these things could be, and illustrated the new birth by one of the most proper similes that could be chosen; but so intent was this great man an making every thing submit to the testimony of his senses that he appears unwilling to believe any thing, unless he can comprehend it. This is the case with many - they profess to believe because they comprehend; but they are impostors who speak thus: there is not a man in the universe that can fully comprehend one operation, either of God or his instrument nature; and yet they must believe, and do believe, though they never did nor ever can fully comprehend, or account for, the objects of their faith.

(3) Nicodemus answered and said unto him, How can these things be?
(3) The secret mystery of our regeneration which cannot be comprehended by man's capacity, is perceived by faith, and that in Christ only, because he is both God on earth, and man in heaven, that is to say, man in such a way that he is God also, and therefore almighty: and God in such a way that he is man also, and therefore his power is made manifest to us.

Nicodemus answered and said unto him,.... Remaining still as ignorant as ever, though Christ had explained the phrase "born again", at which he stumbled, by a being "born of water and of the Spirit", or of the grace of the Spirit of God; and had illustrated this by the free, powerful, and invisible blowing of the wind:
how can these things be? The Arabic version reads, "how can this be?" referring either to the last thing said, that a man's being born of the Spirit, is like the blowing of the wind; or to the explanation of the first expression, that a man should be born of water, and of the Spirit; or to the first assertion itself, that a man should be born again; which notwithstanding the explanation and illustration, seemed as impossible, and as impracticable as ever; or rather to them all, and so the Persic version reads, "how can all these things be?"

Christ's stating of the doctrine and the necessity of regeneration, it should seem, made it not clearer to Nicodemus. Thus the things of the Spirit of God are foolishness to the natural man. Many think that cannot be proved, which they cannot believe. Christ's discourse of gospel truths, John 3:11-13, shows the folly of those who make these things strange unto them; and it recommends us to search them out. Jesus Christ is every way able to reveal the will of God to us; for he came down from heaven, and yet is in heaven. We have here a notice of Christ's two distinct natures in one person, so that while he is the Son of man, yet he is in heaven. God is the "HE THAT IS," and heaven is the dwelling-place of his holiness. The knowledge of this must be from above, and can be received by faith alone.

How, &c.--Though the subject still confounds Nicodemus, the necessity and possibility of the new birth is no longer the point with him, but the nature of it and how it is brought about [LUTHARDT]. "From this moment Nicodemus says nothing more, but has sunk unto a disciple who has found his true teacher. Therefore the Saviour now graciously advances in His communications of truth, and once more solemnly brings to the mind of this teacher in Israel, now become a learner, his own not guiltless ignorance, that He may then proceed to utter, out of the fulness of His divine knowledge, such farther testimonies both of earthly and heavenly things as his docile scholar may to his own profit receive" [STIER].