Catena Aurea on John 18:28–32: Alcuin of York

The passover was strictly the fourteenth day of the month, the day on which the lamb was killed in the evening: the seven days following were called the days of unleavened bread, in which nothing leavened ought to be found in their houses. Yet we find the day of the passover reckoned among the days of unleavened bread: Now the first day of the feast of unleavened bread the disciples came to Jesus, saying unto Him, Where wilt Thou that we prepare for Thee to eat the passover? (Mat. 26:17) And here also in like manner: That they might eat the passover; the passover here signifying not the sacrifice of the lamb, which took place the fourteenth day at evening, but the great festival which was celebrated on the fifteenth day, after the sacrifice of the lamb. Our Lord, like the rest of the Jews, kept the passover on the fourteenth day: on the fifteenth day, when the great festival was held, He was crucified. His immolation however began on the fourteenth day, from the time that He was taken in the garden.