After putting the blood on the door, the Israelites were all commanded to eat unleavened bread that night. that is a picture of our feeding on Christ Himself, the Bread of Life. It's not enough that we trust in His blood, we must feed on His life too. "For if, when we were enemies, we were reconciled to God by the death of his Son; much more, being reconciled, shall we be saved by his life." (Romans 5:10)