Wonder not. This passage has been tortured by commentators in various ways. Some think that Christ reproves the gross ignorance of Nicodemus and other persons of the same class, by saying that it is not wonderful, if they do not comprehend that heavenly mystery of regeneration, since even in the order of nature they do not perceive the reason of those things which fall under the cognizance of the senses. Others contrive a meaning which, though ingenious, is too much forced: that, "as the wind blows freely, so by the regeneration of the Spirit we are set at liberty, and, having been freed from the yoke of sin, run voluntarily to God. Equally removed from Christ's meaning is the exposition given by Augustine, that the Spirit of God exerts his power according to his own pleasure. A better view is given by Chrysostom and Cyril, who say that the comparison is taken from the wind, and apply it thus to the present passage: though its power be felt, we know not its source and cause." While I do not differ greatly from their opinion, I shall endeavor to explain the meaning of Christ with greater clearness and certainty. I hold by this principle, that Christ borrows a comparison from the order of nature. Nicodemus reckoned that what he had heard about regeneration and a new life was incredible, because the manner of this regeneration exceeded his capacity. To prevent him from entertaining any scruple of this sort, Christ shows that even in the bodily life there is displayed an amazing power of God, the reason of which is concealed. For all draw from the air their vital breath; we perceive the agitation of the air, but know not whence it comes to us or whither it departs. If in this frail and transitory life God acts so powerfully that we are constrained to admire his power, what folly is it to attempt to measure by the perception of our own mind his secret work in the heavenly and supernatural life, so as to believe no more than what we see? Thus Paul, when he breaks out into indignation against those who reject the doctrine of the resurrection, on the ground of its being impossible that the body which is now subject to putrefaction, after having been reduced to dust and to nothing, should be clothed with a blessed immortality, reproaches them for stupidity in not considering that a similar display of the power of God may be seen in a grain of wheat; for the seed does not spring until it; has been putrefied, (1-Corinthians 15:36, 37.) This is the astonishing wisdom of which David exclaims, O Lord, how manifold are thy works! in wisdom hast thou made them all, (Psalm 104:24) They are therefore excessively stupid who, having been warned by the common order of nature, do not rise higher, so as to acknowledge that the hand of God is far more powerful in the spiritual kingdom of Christ. When Christ says to Nicodemus that he ought not to wonder, we must not understand it in such a manner as if he intended that we should despise a work of God, which is so illustrious, and which is worthy of the highest admiration; but he means that we ought not to wonder with that kind of admiration which hinders our faith. For many reject as fabulous what they think too lofty and difficult. In a word, let us not doubt that by the Spirit of God we are formed again and made new men, though his manner of doing this be concealed from us.

Marvel not - Wonder not. It is possible that Nicodemus in some way still expressed a doubt of the doctrine, and Jesus took occasion in a very striking manner to illustrate it.

Marvel not that I said unto thee,...., For Nicodemus was quite astonished, at this doctrine of the new birth; it was altogether new to him, and unheard of by him; nor could he understand, nor conceive in what manner it could be:
ye must be born again; in "four" of Beza's copies, it is read "we"; but as Christ was not begotten in a carnal way, or descended not from Adam in the ordinary way of generation, he was not carnal and corrupt, nor in the least tainted with sin; and so stood in no need of regeneration; wherefore such a reading must be rejected. There is a necessity of the regeneration of those, who are the chosen of God, and the redeemed of the Lamb; and of them only can the words be understood; for as for others, they neither can, nor will, nor must be born again: but the people of God "must"; partly because it is the will of God; it is his purpose and resolution, that they shall be regenerated; he has chosen them, through sanctification of the Spirit, unto salvation by Christ: this is the way and method of saving sinners he has fixed upon, namely, not to save them by works of righteousness, but by grace, and according to abundant mercy, through the washing of regeneration, and the renewing of the Holy Ghost: and partly, because of the case and condition of men, which requires it; for whereas the chosen people of God, are predestinated to the adoption of children, and are taken into the family of God, and are heirs to an inheritance, it is necessary they should have a nature, temper, and disposition of mind, suitable to the inheritance they are to enjoy; which they have not in their natural estate, and which is conveyed to them in regeneration: besides, their carnal minds are enmity to God, and it is necessary that they should be friendly to him, which cannot be without regeneration; nor can they, till they are born again, please God, or do those things which are pleasing to him: to which may be added, which Christ has before suggested, and which shows the necessity of it, that without it, no man can either see, or enter into the kingdom of God. To take off the surprise of Nicodemus, our Lord instances in a common natural case, and to which this affair of regeneration may be compared, and by it illustrated.

Marvel not, &c.--If a spiritual nature only can see and enter the kingdom of God; if all we bring into the world with us be the reverse of spiritual; and if this spirituality be solely of the Holy Ghost, no wonder a new birth is indispensable.
Ye must--"Ye, says Jesus, not we" [BENGEL]. After those universal propositions, about what "a man" must be, to "enter the kingdom of God" (John 3:5) --this is remarkable, showing that our Lord meant to hold Himself forth as "separate from sinners."

Marvel not that I said unto thee, Ye must be born again. The necessity is implied in the word kingdom. No one born a citizen of England can become a citizen of the United States without complying with our naturalization laws. The kingdom of God has its naturalization laws, and there is no other way of entrance than to be born of water and of the Spirit. We may not understand all the mysteries of the new birth, any more than we do those of the natural birth, but we can understand what has to be done and what is necessary. Two things are needful: the spirit must be renewed; we must be baptized.

Ye must be born again - To be born again, is to be inwardly changed from all sinfulness to all holiness. It is fitly so called, because as great a change then passes on the soul as passes on the body when it is born into the world.