Exodus 12:7

They shall take of the blood.

It was not enough that the blood of the lamb was Shed, but it must be Sprinkled, denoting the application of the merits of Christ's death to our souls. We must receive the atonement (Romans 5:11).-- M. Henry. The blood had to be sprinkled by. formal act; we receive the blood by. formal act; being buried by baptism into the death of Christ.

Shall strike on the two door-posts.

That the smearing with blood was to be regarded as an act of expiation is evident from the simple fact that. hyssop bush was used for the purpose (v. 22); for sprinkling with hyssop is never prescribed in the law except in connection with purification; whence the sense of expiation (Leviticus 14:49, sqq; Numbers 19:18-19). In Egypt the Israelites had no common altar, and for this reason the houses in which they assembled for the Passover were consecrated as altars; and the persons found in them were thereby removed from the stroke of the destroyer.

The upper door post.

The upper part of the door frame, which extended over the door.