John 13:28

The disciples however understand not the force of the saying, and this (it seems) in accordance with the Divine dispensation, as Christ did not unfold its meaning to them: since in other places indeed we find Him teaching them that He would be delivered into the hands of sinners, and that He would be crucified, and put to death, and would rise again on the third day; but ever charging them by no means to tell this to any man. For His aim was to prevent the prince of this world from knowing who in very nature He was, to the end that He might actually be crucified, and by His crucifixion might destroy death, and effectually accomplish salvation for them that believe on Him. Therefore in accordance with His Divine purpose He conceals the deepest meaning of His words: for as God He ever knows what is best for man.

"Now no one of those at the table knew for what intent He spake this unto him. For some of them thought, because Judas had the money-bag, that Jesus said unto him, Buy those things which we have need of against the feast; or, that he should give something to the poor." The Lord, therefore, had also a money-box, where He kept the offerings of believers, and distributed to the necessities of His own, and to others who were in need. It was then that the custom of having church-money was first introduced, so that thereby we might understand that His precept about taking no thought for the morrow was not a command that no money should be kept by His saints, but that God should not be served for any such end, and that the doing of what is right should not be held in abeyance through the fear of want. For the apostle also has this foresight for the future, when he says: "If any believer hath widows, let him give them enough, that the church may not be burdened, that it may have enough for them that are widows indeed."

(Hom. lxxii. 2.) That thou doest, do quickly, is not a command, or a recommendation, but a reproof, meant to show too that He was not going to offer any hindrance to His betrayal. Now no man at the table knew for what intent He spake this unto him. It is not easy to see, when the disciples had asked, Who is he, and He had replied, He it is to whom I shall give a sop, how it was that they did not understand Him; unless it was that He spoke too low to be heard; and that John lay upon His breast, when he asked the question, for that very reason, i. e. that the traitor might not be made known. For had Christ made him known, perhaps Peter would have killed him. So it was then, that none at the table knew what our Lord meant. But why not John? Because he could not conceive how a disciple could fall into such wickedness: he was far from such wickedness himself, and therefore did not suspect it of others. What they thought He meant we are told in what follows: For some of them thought, because Judas had the bag, that Jesus had said unto him, Buy those things that we have need of against the feast, or, that he should give something to the poor. (Hom. lxxii. 2.) None of the disciples contributed this money, but it is hinted that it was certain women, who, it is said, ministered to Him of their means. But how was it that He Who forbad scrip, and staff, and money, carried bags for the relief of the poor? It was to show thee, that even the very poor, those who are crucified to this world, ought to attend to this duty. He did many things in order to instruct us in our duty.