Exodus 12:19
Seven days shall there be no leaven found in your houses: for whosoever eateth that which is leavened, even that soul shall be cut off from the congregation of Israel, whether he be a stranger, or born in the land. Seven days shall there be no leaven found in your houses: for whosoever eateth that which is leavened, even that soul shall be cut off from the congregation of Israel, whether he be a stranger, or born in the land.
The verse is part of the directions given through Moses before the midnight judgment for Israel's departure from Egypt and preservation from destruction. It belongs to the solemn ordinance of the Passover instituted on the night of the last and most severe plague upon Egypt, a night terrible to the Egyptians and glorious to the people of God. Moses told Pharaoh, the people of Egypt, and the Israelites beforehand the nature and effect of that last plague, while the king and his idolatrous priests still opposed letting Israel go. At that time the people desired their departure from Egypt.
Each family, alone or joined with others, was to slay a lamb or kid without blemish. Its blood was to be sprinkled on the doorway, on the two side-posts and upper door-post, so that the destroying angel at midnight would pass over the houses and not enter. They were to eat the roasted flesh with unleavened bread and bitter herbs at night, with loins girded, shoes on feet, and staff in hand, eating in haste, because it is the Lord's passover. They gathered to eat the Passover supper, and that night the first-born were slain with mourning among the Egyptians.
God delivered Israel from Egypt despite Pharaoh's opposition, and that deliverance enabled the people to keep God's law, to which end God brought them to Sinai to hear the law proclaimed. The unleavened bread eaten at the Passover meal was one of the ceremonies that recalled Israel's deliverance from bondage and was instituted to keep Israel mindful of its deliverance and of God's works, mercy, and loving-kindness. The verse commands that no leaven be found in houses during the seven days of the Passover feast, a requirement expressly enjoined in the law and strictly observed.
The absence of leaven signifies that the leaven of sin must be put away from all who would receive life and nourishment from Christ. The Passover lamb pointed to Christ's death, and the blood on the doorposts symbolized Christ's blood, which cleanses believing sinners from sin and shelters them from God's wrath. The provision of salvation called for people to act in faith.