Where was the Passover lamb's blood to be put on the Israelite houses?
The blood of the Passover lamb was to be struck on the two side posts and on the upper door post—the lintel or headboard—of the house where the Israelites would eat it. In Egypt, this meant the door of their little huts, applying the blood with a piece of hyssop.
Les teaches that the Israelites were to take the blood of that Passover lamb and strike it on the two side posts and on the upper door post of the house wherein they would eat it. He notes they had no fancy homes in slavery in Egypt, so it was the door of their little huts. They were to strike with a piece of hyssop, which was like our ragweed, and put the blood on the two door posts and on the lintel or headboard. Les points out that although they did not know it, this marked the outline of the cross, and certainly that is what God had in mind. The blood was to be a token upon the houses where they were.
And they shall take of the blood, and strike it on the two side posts and on the upper door post of the houses, wherein they shall eat it.
And ye shall take a bunch of hyssop, and dip it in the blood that is in the bason, and strike the lintel and the two side posts with the blood that is in the bason; and none of you shall go out at the door of his house until the morning.