12:17. And you shall observe the feast of the unleavened bread: for in this same day I will bring forth your army out of the land of Egypt, and you shall keep this day in your generations by a perpetual observance.
12:18: The first month, the fourteenth day of the month, in the evening, you shall eat unleavened bread, until the one and twentieth day of the same month, in the evening.
Unleavened bread. . .By this it appears, that our Saviour made use of unleavened bread, in the institution of the blessed sacrament, which was on the evening of the paschal solemnity, at which time there was no leavened bread to be found in Israel.
12:19. Seven days there shall not be found any leaven in your houses: he that shall eat leavened bread, his soul shall perish out of the assembly of Israel, whether he be a stranger or born in the land.
12:20. You shall not eat any thing leavened: in all your habitations you shall eat unleavened bread.
12:21. And Moses called all the ancients of the children of Israel, and said to them: Go take a lamb by your families, and sacrifice the Phase.
12:22. And dip a bunch of hyssop in the blood that is at the door, and sprinkle the transom of the door therewith, and both the door cheeks: let none of you go out of the door of his house till morning.
Sprinkle, etc. . .This sprinkling the doors of the Israelites with the blood of the paschal lamb, in order to their being delivered from the sword of the destroying angel, was a lively figure of our redemption by the blood of Christ.
12:23. For the Lord will pass through striking the Egyptians: and when he shall see the blood on the transom, and on both the posts, he will pass over the door of the house, and not suffer the destroyer to come into your houses and to hurt you.
12:24. Thou shalt keep this thing as a law for thee and thy children for ever.