See the notes at Matthew 26:21-25.

The hand of him that betrayeth me, etc. - What can be desired more, says Dr. Lightfoot, as a demonstration that Judas was present at the eucharist? And, whereas the contrary is endeavored to be proved out of John 13, nothing is made out of nothing; for there is not one syllable throughout that whole chapter of the paschal supper, but of a supper before the feast of the passover.

(6) But, behold, the (i) hand of him that betrayeth me [is] with me on the table.
(6) Christ shows again that he goes willingly to die, although he is not ignorant of Judas' treason.
(i) That is, his practice; the Hebrews used to speak in this way, as in (2-Samuel 14:19): "Is not the hand of Joab with thee in all this?"

But behold the hand of him that betrayeth me,.... By the "hand" is meant, not figuratively the counsel, contrivance, and conspiracy of Judas to betray him, as the word is used in 2-Samuel 14:19 but literally the hand of Judas, which was then dipping in the dish with Christ, Matthew 26:23 and it follows here, is
with me on the table; and is an aggravation of his sin, that one that sat with him at his table, ate bread with him, and dipped his morsel in the same dish, should be the betrayer of him, according to the prophecy in Psalm 41:9 as well as describes and points at the person that should do this action, even one of his disciples; for which disciples, he had just now said, his body is given, and his blood is shed. The phrase, "with me", is left out in the Syriac and Persic versions. From Luke's account it appears most clearly, that Judas was not only at the passover, but at the Lord's supper, since this was said when both were over.

How unbecoming is the worldly ambition of being the greatest, to the character of a follower of Jesus, who took upon him the form of a servant, and humbled himself to the death of the cross! In the way to eternal happiness, we must expect to be assaulted and sifted by Satan. If he cannot destroy, he will try to disgrace or distress us. Nothing more certainly forebodes a fall, in a professed follower of Christ, than self-confidence, with disregard to warnings, and contempt of danger. Unless we watch and pray always, we may be drawn in the course of the day into those sins which we were in the morning most resolved against. If believers were left to themselves, they would fall; but they are kept by the power of God, and the prayer of Christ. Our Lord gave notice of a very great change of circumstances now approaching. The disciples must not expect that their friends would be kind to them as they had been. Therefore, he that has a purse, let him take it, for he may need it. They must now expect that their enemies would be more fierce than they had been, and they would need weapons. At the time the apostles understood Christ to mean real weapons, but he spake only of the weapons of the spiritual warfare. The sword of the Spirit is the sword with which the disciples of Christ must furnish themselves.

(See on John 13:21, &c.).

The incident concerning the betrayal mentioned in these verses occurred before the Lord's Supper was eaten (Matthew 26:21). It seems probable, from John 13:21-35, that Judas left before the supper. On this passage, see notes on Matthew 26:21-25.

The hand of him that betrayeth me is with me on the table - It is evident Christ spake these words before he instituted the Lord's Supper: for all the other evangelists mention the sop, immediately after receiving which he went out: John 13:30. Nor did he return any more, till he came into the garden to betray his Master. Now this could not be dipped or given, but while the meat was on the table. But this was all removed before that bread and cup were brought.