God said to the children of Israel on that dark night down in Egypt, that the blood should be to them for a token, and when He should see the blood he would pass over.
You will remember that the first-born in all the houses in Egypt were to be killed, but God was going to pass over every house where the blood was upon the door posts and lintels. What blood? The blood of the lamb. They were to be perfectly safe if the blood was there, for God had said it. (Read carefully the account in Exodus 12.) The lamb's blood pointed to Jesus' blood to be shed long years after, and just as the children of Israel were perfectly safe on the dark night sheltered by the blood of the lamb, so every one sheltered by the blood of God's lamb, Jesus, is just as safe as in the presence of God. As many as received Him, (Jesus) to them gave he power to become the sons of God, even to them that believe on his name.—Selected.