Luke 22:7=Then came the day of unleavened bread, when the passover must be killed.
Mark 14:12=And the first day of unleavened bread, when they killed the passover, HIS, disciples said unto HIM, where wilt thou that we go and prepare that thou mayest eat the passover.
Exodus 12:18= In the first month, on the 14th day of the month at evening, ye shall eat unleavened bread, until the (one and twentieth day=21 of the month at evening.