21 Then Moses called for all the elders of Israel, and said unto them, Draw out and take you a lamb according to your families, and kill the passover.
22 And all of you shall take a bunch of hyssop, and dip it in the blood that is in the basin, and strike the lintel and the two side posts with the blood that is in the basin; and none of you shall go out at the door of his house until the morning.
23 For the LORD will pass through to strike the Egyptians; and when he sees the blood upon the lintel, and on the two side posts, the LORD will pass over the door, and will not suffer the destroyer to come in unto your houses to strike you.