And he sent Peter and John, saying, Go and prepare us the {d} passover, that we may eat.

(d) The lamb which was the symbol of the passover: And this is said using the figure of speech metonymy, which is often used when talking about the sacraments.

People's New Testament

22:7,8 Then came the day of unleavened bread. Josephus calls both the fourteenth and fifteenth of Nisan, the day of unleavened bread. I have followed Neander, Tischendorf, Winer, Alford, Ellicott, Erasmus, Grotius, Calvin and others in the view that the Lord's passover was eaten one day before the Jews ate theirs, and that he died about the time that the paschal lambs were slain for the Jews' passover. See notes on Joh 18:28 19:31.

Matthew Henry's Concise Commentary

22:7-18 Christ kept the ordinances of the law, particularly that of the passover, to teach us to observe his gospel institutions, and most of all that of the Lord's supper. Those who go upon Christ's word, need not fear disappointment. According to the orders given them, the disciples got all ready for the passover. Jesus bids this passover welcome. He desired it, though he knew his sufferings would follow, because it was in order to his Father's glory and man's redemption. He takes his leave of all passovers, signifying thereby his doing away all the ordinances of the ceremonial law, of which the passover was one of the earliest and chief. That type was laid aside, because now in the kingdom of God the substance was come.