Mark 14:19

But they began to be sorrowful, and to say to him one by one, "Is it I?" And surely the eleven apostles knew that they were not contemplating anything like this against the Lord, but they trusted the teacher more than themselves; and fearing their own weakness, they sorrowfully inquired about a sin of which they had no consciousness.

All the disciples then are touched by the Lord; so that there is amongst them the harmony of the harp, all the well attuned strings answer with accordant tone; for it goes on: And they began to be sorrowful, and to say unto him one by one, Is it I? One of them however, unstrung, and steeped in the love of money, said, Is it I, Lord? as Matthew testifies.

And being exceedingly saddened they began each one to say: Is it I, Lord?. But someone will ask: if the eleven apostles were of good conscience (since they were clean of any betrayal of their master), why were they saddened at the hearing of it, as though it could come to pass that one of them was he of whom it was spoken? But I judge that each of the disciples knew, from those things which Jesus had taught, that human nature is changeable and turnable to evil, and that in the struggle "against the principalities and powers and rulers of this world of darkness" it can come to pass that a man falls, either circumvented or having suffered force from the adversary powers to the accomplishing of evil. Considering this, therefore, each of the disciples, lest perhaps he himself were the one who had been foreknown as the betrayer, were saddened greatly, because it had been said to them: one of you will betray me, and they began to say, as though each one not knowing what was to be concerning himself: Is it I, Lord? And if it has reason that for this cause each of them, fearing, said: Is it I, Lord, then concerning all future things it must be feared by us who are weak, who have not yet received the wisdom of perfection, according to which the apostle says: "for I am confident that neither death nor life" and the rest "can separate us from the love of God, which is in Christ Jesus". But he who is not yet perfect doubts concerning himself, as though he too could fall; according to which human weakness Paul, writing to the Corinthians, said: "but I chastise my body and bring it into servitude, lest perhaps, having preached to others, I myself be made reprobate". And see: what he says, "lest perhaps, having preached to others, I myself be made reprobate", he so pronounces as one fearing, lest perhaps he too could both fall and become reprobate; but what he said, "I am confident" and the rest, is of a confident and firm man on account of his perfection, since a thousand contrary things have not the strength to separate him "from the love of Christ". But that the apostles were still weak and rightly feared is manifest from that which he says who knew the purpose of each one, that "you shall all suffer scandal in me in this night". And that one who purposes better things is sometimes turned aside to malice, conquered in the struggle of the contrary powers, is manifest…