Exodus 12:13 - Clarke's commentary and critical notes on the Bible

And the blood shall be to you for a token upon the houses where ye are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt. The blood shall be to you for a token - It shall be the sign to the destroying angel, that the house on which he sees this blood sprinkled is under the protection of God, and that no person in it is to be injured. See Clarke on Exodus 12:11 (note).