Bede the Venerable
Catena Aurea · Markusevangelium 14
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? And he sendeth forth two of his disciples, and saith unto them, Go ye into the city, and there shall meet you a man bearing a pitcher of water: follow him. And wheresoever he shall go in, say ye to the goodman of the house, The Master saith, Where is the guestchamber, where I shall eat the Passover with my disciples? And he will shew you a large upper room furnished and prepared: there make ready for us. And his disciples went forth, and came into the city, and found as he had said unto them: and they made ready the Passover.
(ubi sup.) He means by the first day of the Passover the fourteenth day of the first month, when they threw aside leaven, and were wont to sacrifice, that is, to kill the lamb at even. The Apostle explaining this says, Christ our Passover is sacrificed for us. (1 Cor. 5:7) For although He was crucified on the next day, that is, on the fifteenth moon, yet on the night when the lamb was offered up, He committed to His disciples the mysteries of His Body and Blood, which they were to celebrate, and was seized upon and bound by the Jews; thus He consecrated the beginning of His sacrifice, that is, of His Passion.