And though he had done so many signs. That no man may be disturbed or perplexed at seeing that Christ was despised by the Jews, the Evangelist removes this offense, by showing that he was supported by clear and undoubted testimonies, which proved that credit was due to him and to his doctrine; but that the blind did not behold the glory and power of God, which were openly displayed in his miracles. First, therefore, we ought to believe that it was not owing to Christ that the Jews did not place confidence in him, because by many miracles he abundantly testified who he was, and that it was therefore unjust and highly unreasonable that their unbelief should diminish his authority. But as this very circumstance might lead many persons to anxious and perplexing inquiry how the Jews came to be so stupid, that the power of God, though visible, produced no effect upon them, John proceeds further, and shows that faith does not proceed from the ordinary faculties of men, but is an uncommon and extraordinary gift of God, and that this was anciently predicted concerning Christ, that very few would believe the Gospel.

So many miracles - This does not refer to any miracles performed on this occasion, but to all his miracles performed in view of the nation, in healing the sick, opening the eyes of the blind, raising the dead, etc. John here gives the summary or the result of all his work undeniable proof of his being the Messiah, yet the nation did not believe on him.
Before them - Before the Jewish nation. Not in the presence of the people whom he was then addressing, but before the Jewish people.
They believed not - The Jewish nation did not believe as a nation, but rejected him.

Yet they believed not on him - Though the miracles were wrought for this very purpose, that they might believe in Christ, and escape the coming wrath, and every evidence given that Jesus was the Messiah, yet they did not believe; but they were blinded by their passions, and obstinately hardened their hearts against the truth.

(9) But though he had done so many miracles before them, yet they believed not on him:
(9) Faith is not of nature, but of grace.

But though he had done so many miracles before them,.... Openly, and in the presence of them; meaning those miracles which were done at Jerusalem, as those which brought Nicodemus to him, and to an acknowledgment of him as a teacher sent from God; and particularly the cure of the lame man at Bethesda's pool, the giving sight to the man that was born blind, by anointing his eyes with clay, and sending him to wash in the Pool of Siloam, and the raising Lazarus from the dead at Bethany, which was within two miles of Jerusalem, in the presence of many of them who were come there to comfort Martha and Mary. Yet
they believed not on him; the miracles done by Christ before their eyes, which they could not deny, nor disprove, and were so many, and so great, were aggravations of their unbelief; and such indeed is the nature of that sin, and so deeply rooted is it, that the most powerful means, and mighty works, will not bring a person to believe in Christ, without the powerful and efficacious grace of God.

Observe the method of conversion implied here. Sinners are brought to see the reality of Divine things, and to have some knowledge of them. To be converted, and truly turned from sin to Christ, as their Happiness and Portion. God will heal them, will justify and sanctify them; will pardon their sins, which are as bleeding wounds, and mortify their corruptions, which are as lurking diseases. See the power of the world in smothering convictions, from regard to the applause or censure of men. Love of the praise of men, as a by-end in that which is good, will make a man a hypocrite when religion is in fashion, and credit is to be got by it; and love of the praise of men, as a base principle in that which is evil, will make a man an apostate, when religion is in disgrace, and credit is to be lost for it.

It is the manner of this Evangelist alone to record his own reflections on the scenes he describes; but here, having arrived at what was virtually the close of our Lord's public ministry, he casts an affecting glance over the fruitlessness of His whole ministry on the bulk of the now doomed people.
though he had done so many miracles--The word used suggests their nature as well as number.

Yet they believed not on him. They had a kind of intellectual faith, but were filled with doubts when they could not understand. There was no real trust.

Though he had done so many miracles before them - So that they could not but see them.