After two days is - the feast of the Passover.
See the notes at Matthew 12:1-8. The festival of the Passover was designed to preserve among the Jews the memory of their liberation from Egyptian servitude, and of the safety of their first-born in that night when the firstborn of the Egyptians perished, Exodus. 12. The name "Passover" was given to the feast because the Lord "passed over" the houses of the Israelites without slaying their first-born, while the Egyptians were cut off, Exodus 12:13. It was celebrated seven days, namely, from the 15th to the 21st of the month Abib or Nisan (April), Exodus 12:15-20; Exodus 23:15. During all this period the people ate unleavened bread, and hence the festival was sometimes called the "feast of unleavened bread," Exodus 12:18; Leviticus 23:6. On the evening of the fourteenth day, all the leaven or yeast in the family was removed with great care, as it is to the present time - a circumstance to which the apostle alludes in 1-Corinthians 5:7.
On the tenth day of the month the master of a family separated a lamb or a goat of a year old from the flock Exodus 12:1-6, which he killed on the 14th day before the altar, Deuteronomy 16:2, Deuteronomy 16:5-6. The lamb was commonly slain at about 3 o'clock p. m.. The blood of the paschal lamb was, in Egypt, sprinkled on the door-posts of the houses; afterward it was poured by the priests at the foot of the altar, Exodus 12:7. The lamb thus slain was roasted whole, with two spits thrust through it - one lengthwise and one transversely - crossing each other near the forelegs, so that the animal was in a manner, crucified. Not a bone of it might be broken - a circumstance strongly representing the sufferings of our Lord Jesus, the Passover slain for us, John 19:36; 1-Corinthians 5:7. Thus roasted, the lamb was served up with wild and bitter herbs, Not fewer than ten, nor more than twenty persons, were admitted to these sacred feasts. At first it was observed with their loins girt about, with sandals on their feet, and with all the preparations for an immediate journey. This, in Egypt, was significant of the haste with which they were about to depart from the land of bondage. The custom was afterward retained.
The order of the celebration of this feast was as follows: The ceremony commenced with drinking a cup of wine mingled with water, after having given thanks to God for it. This was the "first cup." Then followed the "washing of hands," with another short form of thanksgiving to God. The table was then supplied with the provisions, namely, the bitter salad, the unleavened bread, the lamb, and a thick sauce composed of dates, figs, raisins, vinegar, etc. They then took a small quantity of salad, with another thanksgiving, and ate it; after which, all the dishes were removed from the table, and a second cup of wine was set before each guest, as at first. The dishes were removed, it is said, to excite the curiosity of children, and to lead them to make inquiry into the cause of this observance. See Exodus 12:26-27. The leading person at the feast then began and rehearsed the history of the servitude of the Jews in Egypt, the manner of their deliverance, and the reason of instituting the Passover. The dishes were then returned to the table, and he said, "This is the Passover which we eat, because that the Lord passed over the houses of our fathers in Egypt;" and then, holding up the salad and the unleavened bread, he stated the design, namely, that the one represented the bitterness of the Egyptian bondage, and the other the suddenness of their deliverance.
This done, he repeated Psalm 113:1-9; Psalm 114:1-8, offered a short prayer, and all the company drank the wine that had been standing some time before them. This was the "second cup." The hands were then again washed, and the meal then eaten with the usual forms and solemnities; after which they washed the hands again, and then drank another cup of wine, called "the cup of blessing," because the leader was accustomed in a particular manner, over that cup, to offer thanks to God for his goodness. This is the cup which our Saviour is supposed to have taken when he instituted the Lord's Supper, called by Paul "the cup of blessing," 1-Corinthians 10:16. There was still another cup, which was drunk when they were about to separate, called the "Hallel," because in connection with it they were accustomed to repeat the lesser Hallel, or Ps. 115; 116; Psalm 117:1-2; 118. In accordance with this, our Saviour and his disciples sang a hymn as they were about to go to the Mount of Olives, Matthew 26:30. It is probable that our Saviour complied with these rites according to the custom of the Jews. While doing it, he signified that the typical reference of the Passover was about to be accomplished, and he instituted in place of it "the supper" - the communion - and, of course, the obligation to keep the Passover then ceased.
The Son of man is betrayed - Will be betrayed. He did not mean to say that they then knew that he would be betrayed, for it does not appear that they had been informed of the precise time; but they knew that the Passover was at hand, and he then informed them that he would be betrayed.
To be crucified - To be put to death on the cross. See the notes at Matthew 27:35.

The passover - A feast instituted in Egypt, to commemorate the destroying angel's passing over the houses of the Israelites, when he slew the firstborn of the Egyptians. See the whole of this business largely explained in the Notes on Exodus 12:1-27 (note). This feast began on the fourteenth day of the first moon, in the first month, Nisan, and it lasted only one day; but it was immediately followed by the days of unleavened bread, which were seven, so that the whole lasted eight days, and all the eight days are sometimes called the feast of the passover, and sometimes the feast or days of unleavened bread. See Luke 22:1-7. The three most signal benefits vouchsafed to the Israelites were,
1. The deliverance from the slavery of Egypt; to commemorate which they kept the feast of unleavened bread, and the passover.
2. The giving of the law; to commemorate which, they kept the feast of weeks.
3. Their sojourning in the wilderness, and entrance into the promised land; to commemorate which, they kept the feast of tabernacles.
See these largely explained, Exodus 23:14 (note); Leviticus 23:2-40 (note).
The Son of man is betrayed, (rather delivered up), to be crucified - With what amazing calmness and precision does our blessed Lord speak of this awful event! What a proof does he here give of his prescience in so correctly predicting it; and of his love in so cheerfully undergoing it! Having instructed his disciples and the Jews by his discourses, edified them by his example, convinced them by his miracles, he now prepares to redeem them by his blood! These two verses have no proper connection with this chapter, and should be joined to the preceding.

(2) Ye know that after two days is [the feast of] the passover, and the Son of man is betrayed to be crucified.
(2) God himself and not man appoints the time that Christ should be crucified.

Ye know that after two days is the feast of the passover,.... Which was kept in commemoration of the deliverance of the Israelites from Egypt; and was typical of Christ the passover, who was now to be sacrificed for his people. This was said on Tuesday, and on the Thursday following, the passover began. Christ speaks of this as a thing well known to the disciples, as it must be, since it always began on a certain day, the fourteenth of the month Nisan; which month answered to part of our March, and part of our April; and though there was very frequently an intercalation of a whole month in a year, made by the sanhedrim, to keep their festivals regularly in the proper season of the year; yet previous public notice was always given of this, either by fixing a paper upon the door of the sanhedrim (r), signifying such an intercalation made, which served for the inhabitants of Jerusalem; or by sending messengers with letters into all distant places (s), acquainting them with it. So that the times of these festivals were always well known; even to the common people:
and the son of man is betrayed to be crucified; it must not be thought that this was equally known by the disciples, as the former; for though they might know, or at least remember, that Christ had told them that he should suffer many things of the priests, Scribes, and elders, who would deliver him to the Gentiles, to be crucified; yet might not understand that this passover was to be the time, when this should be done: by "the son of man", Christ means himself, who was truly and really man, the seed of the woman, the son of Abraham and of David; a character by which the Messiah is described in the Old Testament, Psalm 80:17 Daniel 7:13, and hence frequently used by Christ of himself; which, as it expresses the truth of his human nature, so the weaknesses and infirmities he bore in it; and is very properly used here, when he is speaking of his being to be betrayed and crucified. What he says of himself is, that he is "betrayed"; that is, is to be betrayed, or will be betrayed, meaning at the passover, which was to be in two days time. Christ speaks of his being betrayed, as if it was already done; not only because it was so near being done, there being but two days before it would be done; but because it was a sure and certain thing, being determined in the purpose of God, and foretold in prophecy that it should be; and besides, Judas had now resolved upon it within himself, and was forming a scheme how to bring it about. And this respects not only the act of Judas in betraying him into the hands of the chief priests, but also the delivery, as the word here used signifies, of him by them, to the Roman governors; for they, as Stephen says, were also his betrayers and murderers; yea, it may include the delivery of him by Pilate, to the Jews and Roman soldiers; and the rather, because it follows, "to be crucified"; which was a Roman, and not a Jewish punishment. This was typified by the lifting up the brazen serpent on a pole, and foretold by the prophets of the Old Testament, Psalm 22:16, and predicted by Christ himself, sometimes more covertly, John 12:32, and sometimes in express words, Matthew 20:19, and was a very painful and shameful death, and which showed him to be made a curse for his people. It appears from hence; that the crucifixion and death of Christ, were not casual and contingent events, but were determined by the counsel of God, with all circumstances attending: the betraying and delivery of him were by the determinate counsel and foreknowledge of God; and not only his death, but the manner of it by crucifixion, was pointed out in prophecy, and was a certain thing; and the very time of his death was fixed; which shows the early concern of God for the salvation of his people, and his wonderful grace and mercy to them: and it is clear from hence, that Christ had perfect knowledge of all this: he knew not only that he should be betrayed, but he knew from the beginning who would betray him; he not only knew that he should die, but he knew what kind of death he should die, even the death of the cross; and he knew the exact time when he should die, that it would be at the following passover, which was just at hand; and he had suggested this to his disciples, and therefore he speaks of it as a thing known unto them; at least what they might have known, and concluded from what he had said to them, Matthew 20:18, and the whole is a considerable proof of his being God omniscient. And he thought fit to put his disciples in mind of it, because the time drew nigh; that their memories being refreshed with it, they might be prepared for it, and not be surprised, shocked, and offended at it, when it came to pass; which shows the tender concern our Lord had for them.
(r) Targum in Cant. vii. 4. (s) Maimon Hilch. Kiddush Hachodesh, c. 4. sect. 17.

After two days. After Wednesday and Thursday. The day indicated is Friday.
The passover cometh. For the origin of this feast, see Exodus 12:1-14. It was really the Jewish emancipation day, the greatest of their feasts, and the paschal lamb was a type of the slain Christ.

After two days is the passover - The manner wherein this was celebrated gives much light to several circumstances that follow. The master of the family began the feast with a cup of wine, which having solemnly blessed, he divided among the guests, Luke 22:17. Then the supper began with the unleavened bread and bitter herbs; which when they had all tasted, one of the young persons present, according to Exodus 12:26, asked the reason of the solemnity. This introduced the showing forth, or declaration of it: in allusion to which we read of showing forth the Lord's death, 1-Corinthians 11:26. Then the master rose up and took another cup, before the lamb was tasted. After supper, he took a thin loaf or cake, which he broke and divided to all at the table, and likewise the cup, usually called the cup of thanksgiving, of which he drank first, and then all the guests. It was this bread and this cup which our Lord consecrated to be a standing memorial of his death.