Exodus 12:23 in the King James Version
For the LORD will pass through to smite the Egyptians; and when he seeth 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 smite you.
Context
22 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 door posts with the blood that is in the basin. None of you shall go out of 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 on the lintel, and on the two door posts, the LORD will pass over the door, and will not allow the destroyer to come in to your houses to strike you.
24 You shall observe this thing for an ordinance to you and to your sons forever.