But we know whence this man is. Here we see not only how great is the blindness of men, when they ought to judge about the things of God, but this vice is almost natural to them, to be ingenious in contriving what may hinder them from arriving at the knowledge of the truth. It is frequently, indeed, from the craft of Satan that offenses arise, which cause many to turn away from Christ; but though the road were plain and smooth, every man would contrive an offense for himself. So long as the rulers were opposed to Christ, their unbelief would of itself have kept back this multitude; but when that obstacle has been removed, they contrive a new reason for themselves, that they may not come to the faith. And even though it were proper that they should be influenced by the example of their rulers, they are so far from following what is right, that they willingly stumble at the first step. Thus it frequently happens, that men who had begun well fall away quickly, unless the Lord conduct them to the very end of their career. But when Christ shall come. The argument by which they obstruct their own progress is this: "The Prophets have testified that the origin of Christ will be unknown. Now we know whence this man is, and therefore we cannot reckon him to be the Christ." Hence we are reminded how pernicious it is to mangle the Scriptures, and even Christ himself, so as not to admit more than the half of him. God promised that the Redeemer would be of the seed of David; but he frequently claims this office as peculiar to himself; therefore, he must have been God manifested in the flesh, that he might be the Redeemer of his Church. Thus Micah points out the place where Christ would be born. Out of thee, Bethlehem, he says, a Prince shall come, to govern my people But, immediately afterwards, he speaks of another going forth which is far loftier, and then he says that it is hidden and secret, (Micah 5:2.) Yet those wretched men, when they perceived in Christ nothing but what is liable to contempt, draw the absurd conclusion, that he is not the person who had been promised. On the mean condition of Christ in the flesh let us therefore learn to look in such a manner, that this state of humiliation, which is despised by wicked men, may raise us to his heavenly glory. Thus Bethlehem, where the man was to be born, will be to us a door by which we may enter into the presence of the eternal God.

Howbeit - But. They proceeded to state a reason why they supposed that he could not be the Messiah, whatever the rulers might think.
We know this man whence he is - We know the place of his birth and residence.
No man knoweth whence he is - From Matthew 2:5, it appears that the common expectation of the Jews was that the Messiah would be born at Bethlehem; but they had also feigned that after his birth he would be hidden or taken away in some mysterious manner, and appear again from some unexpected quarter. We find allusions to this expectation in the New Testament, where our Saviour corrects their common notions, Matthew 24:23; "Then if any man shall say unto you, Lo, here is Christ, or there, believe it not." And again John 7:26, "If they shall say unto you, Behold, he is in the desert, go not forth; behold, he is in the secret chambers, believe it not." The following extracts from Jewish writings show that this was the common expectation: "The Redeemer shall manifest himself, and afterward be hid. So it was in the redemption from Egypt. Moses showed himself and then was hidden." So on the passage, Song 2:9 - "My beloved is like a roe or a young hart" - they say: "A roe appears and then is hid; so the Redeemer shall first appear and then be concealed, and then again be concealed and then again appear." "So the Redeemer shall first appear and then be hid, and then, at the end of 45 days, shall reappear, and cause manna to descend." See Lightfoot. Whatever may have been the source of this opinion, it explains this passage, and shows that the writer of this gospel was well acquainted with the opinions of the Jews, however improbable those opinions were.

No man knoweth whence he is - The generality of the people knew very well that the Messiah was to be born in Bethlehem, in the city, and of the family, of David; see John 7:42. But, from Isaiah 53:8, Who shall declare his generation? they probably thought that there should be something so peculiarly mysterious in his birth, or in the manner of his appearing, that no person could fully understand. Had they considered his miraculous conception, they would have felt their minds relieved on this point. The Jews thought that the Messiah, after his birth, would hide himself for some considerable time; and that when he began to preach no man should know where he had been hidden, and whence he had come. The rabbins have the following proverb: Three things come unexpectedly:
1. A thing found by chance.
2. The sting of a scorpion: and,
3. The Messiah.
It was probably in reference to the above that the people said, No man knoweth whence he is. However, they might have spoken this of his parents. We know that the Messiah is to be born in Bethlehem, of the family of David; but no man can know his parents: therefore they rejected him: John 6:42, Is not this Jesus, the son of Joseph, whose father and mother we know?

(11) Howbeit we know this man whence he is: but when Christ cometh, no man knoweth whence he is.
(11) Men are very wise to have checks and balances for their own thoughts.

Howbeit, we know this man whence he is,.... They signify, that if the rulers had altered their minds, and had gone into the belief of Jesus of Nazareth being the Messiah, they should not follow them in it, for this reason; because they knew from whence he came; meaning not so much the place of his birth, which they supposed was Galilee, and Nazareth in Galilee, in which they were mistaken, as the manner of his birth, which they could account for: they pretended to know his extract, that he was the son of Joseph and Mary, that he was begotten in wedlock, and was born as other persons are; there was no difficulty with them in accounting for his coming into the world, no more than any other ordinary person; his descent from Joseph and Mary was well known to them, and to be accounted for in a rational way, and therefore concluded he could not be the Messiah:
but when Christ cometh, no man knoweth whence he is; they knew the place from whence he was to come; so the chief priests and Scribes did, Matthew 2:4; and so did these Jews, John 7:42. They knew he would come from Bethlehem, and they knew that he would come out of the seed of David; but then he was to be born of a virgin, according to Isaiah 7:14, and such a coming into the world was not to be known, reasoned upon, and accounted for: wherefore since Jesus, according to the notion of these men, came into the world in the common and ordinary way, they thought they had an invincible argument against his being the Messiah; and therefore, let their rulers do what they would, for their parts, they were determined to reject him: and because it could not be known from whence the Messiah should come; hence the ancient Jews used to call him the seed which comes from another place; not from the place from whence seed ordinarily comes, from the loins of men, but from some other place they knew not where: their words are very remarkable on that passage in Genesis 4:25, "and she called his name Seth, for God hath appointed me another seed", &c. This observation is made by R. Tanchuma, in the name of R. Samuel (d); says he,
"she has respect to that seed, which is he that comes, , "from another place", and what is this? this is the King Messiah.''
And elsewhere (e), the same Rabbi observes on those words in Genesis 19:32, "that we may preserve seed of our father": it is not written, "that we may preserve a son of our father", but "that we may preserve seed of our father"; that seed which is he that comes from "another place"; and what is this? this is the King Messiah. The modern Jews (f) endeavour to explain away the sense of this phrase, "another seed", as if it regarded strange seed; and that the sense of the expression is only, that the Messiah should spring from the family of Moab, and from Ruth the Moabitess: nor is their sense what Aquinas (g) at tributes to the Jewish Rabbins,
"that the more noble part of that mass, of which Adam was made, remained untouched (by sin), and was afterwards transfused into Seth; and so through all descending from him, unto Joakim, or Eliakim, or Heli, the father of the virgin, out of which the body of the blessed Virgin was made:''
which is no other than a Popish device, fathered upon the Jews, and made for the sake of the, Virgin Mary, rather than for the sake of Christ. But their meaning is, that Christ should not be gotten of man, or come into the world in the ordinary way of generation, but should be born of a virgin; and so it could not be known, and accounted for from whence he was, or from whence that seed was of which he was made. The angel gives the best account of this in Luke 1:35, a body was prepared for Christ by the Lord; it was conceived by the power of the Holy Ghost; his birth of a virgin was miraculous; it is beyond the comprehension of men, and cannot explained by any mortal; from whence he is it cannot be said; no man can be pointed to as his father; all that can be said is, he was made of a woman, a virgin.
(d) Bereshit Rabba, sect. 23. fol. 20. 4. Midrash Ruth, fol. 36. 1. (e) Bereshit Rabba, sect. 51. fol. 46. 1. Midrash Ruth, fol. 35. 4. (f) Mattanot Cehunah & Jade Moseh in ib. (g) In 3 sent distinct. 3. art. 2.

Howbeit we know this man, &c.--This seems to refer to some current opinion that Messiah's origin would be mysterious (not altogether wrong), from which they concluded that Jesus could not be He, since they knew all about His family at Nazareth.

When Christ cometh, none knoweth whence he is - This Jewish tradition was true, with regard to his Divine nature: in that respect none could declare his generation. But it was not true with regard to his human nature, for both his family and the place of his birth were plainly foretold.