Matthew 26:2

After two days is the feast of the passover; this was a feast of the Jews, kept annually from the 15th to the 21st of their month Abib, answering in part to our April, in commomoration of God's passing over the houses of the Israelites, and not entering in to slay their first-born, when he slew the first-born of the Egyptians. Exodus 12:1-30.

The Son of man is betrayed to be crucified; as our Lord Jesus was the true sacrifice prefigured by the paschal lamb, it was proper that he, the great Antitype, should die at the passover, when the lamb that typified him was slain.