They began every one of them to say to him. I do not think that the disciples were alarmed, as persons struck with terror are wont to give themselves uneasiness without any reason; but, abhorring the crime, they are desirous to clear themselves from the suspicion of it. It is, indeed, a mark of reverence, that when indirectly blamed, they do not reply angrily to their Master, but each person constitutes himself his own judge, (as the object which we ought chiefly to aim at is, to be acquitted by his own mouth;) but, relying on a good conscience, they wish to declare frankly how far they are from meditating such a crime.

They were exceeding sorrowful - John says John 13:22 "they looked one on another, doubting of whom he spake" - that is, they anxiously looked one at another, conscious each one, except Judas, of no such intention, and each one beginning to examine himself to find whether he was the person intended.
This showed their innocence, and their attachment to Jesus. It showed how sensitive they were to the least suspicion of the kind. It showed that they were willing to know themselves, thus evincing the spirit of the true Christian. Judas only was silent, and was the last to make the inquiry, and that after he had been plainly pointed out Matthew 26:25, thus showing:
1. that guilt is slow to suspect itself;
2. that it shrinks from the light;
3. that it was his purpose to conceal his intention; and,
4. that nothing but the consciousness that his Lord knew his design could induce him to make inquiry.
The guilty would, if possible, always conceal their crimes. The innocent are ready to suspect that they may have done wrong. Their feelings are tender, and they inquire with solicitude whether there may not be something in their bosoms, unknown to themselves, that may be a departure from right feeling.

They were exceeding sorrowful - That is, the eleven who were innocent; and the hypocritical traitor, Judas, endeavored to put on the appearance of sorrow. Strange! Did he not know that Christ knew the secrets of his soul! Or had his love of money so far blinded him, as to render him incapable of discerning even this, with which he had been before so well acquainted?

And they were exceeding sorrowful,.... Partly that Christ should be betrayed at all, into the hands of his enemies, by whom they knew he would be ill used; and partly, that so vile an action should be done, by one from among themselves; and greatly, because they knew not, nor could not conceive, who of them could be guilty of such an horrid sin:
and began everyone of them to say unto him, Lord, is it I? excepting Judas, who afterwards spoke for himself. This they said, though conscious to themselves the thing had never entered into their hearts; nor had they taken any step towards it, but with their whole souls abhorred it; yet, as knowing the treachery and deceitfulness, of their hearts, which they could not trust to; and fearing lest should they be left thereunto, they might commit such a dreadful iniquity; and as desirous of being cleared by Christ from any such imputation, and even from all suspicion of anything of this kind.

Lord, is it I? Not one of them ventures to question the truth of the Lord's prophecy; and each asks the personal question, "Is it I?" No one accuses, even by implication, his neighbor.