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.
When I see the blood, I will pass over you. This strong anthropomorphic expression (cf. Genesis 9:16), which, of course, is not to be literally understood, as if the Divine Being possessed visual organs, or needed actually to behold an object, conveys an idea that the sign was an essential means of deliverance and security to the Israelites. It was not intended merely for the confirmation of their faith, but implied that the blood was symbolical of the atonement which the sacrifice of the paschal lamb had made, and from regard to whose typical efficacy they should be exempted from the judgment that was impending upon the Egyptians.