Matthew Poole and continuators on Exodus 12:13

13 And the blood shall be to you for a token upon the houses where you 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.

Both to you, as he now said, a sign and a pledge to confirm your faith in the expectation of the promised deliverance; and to the Angel, that he may know and pass over your houses, as the following words intimate. See on ver. 7.

This is spoken of God after the manner of men; the sence is, If I find, that you keep the condition which I require, you may expect the priviledge which I have promised you; otherwise not.

Marginal references: Heb. for a destruction.