The blood shall be to you for a token. — Rather, the blood shall be for a token for you: i.e., it shall be a token to Me on your behalf. (See the comment on Exodus 12:7, and compare Exodus 12:23.)
Related Commentaries of Exodus 12:13
Exodus 12:13
13 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 destroyd you, when I smite the land of Egypt.