Exodus 12:13

13 But the blood on your doorposts will serve as a sign, marking the houses where you are staying. When I see the blood, I will pass over you. This plague of death will not touch you when I strike the land of Egypt.

Exodus 12:13 Meaning and Commentary

Exodus 12:13

And the blood shall be to you for a token upon the houses
where you are
The blood of the passover lamb being sprinkled on the two sideposts and upper doorposts of the houses inhabited by the Israelites, or where they were eating the passover; this should be a sign or token to them of the Lord's making good his promises, to them, and so of their safety, and to the destroying angel not to enter therein, but pass by and save them:

and when I see the blood, I will pass over you;
for which reason this ordinance now instituted was called the passover, because the Lord, on sight of the blood sprinkled, passed over the houses of the Israelites to those of the Egyptians; or "leaped", as Jarchi says, the word signifies, skipped from one Egyptian house to another, passing by that of the Israelites:

and the plague shall not be upon you, to destroy you, when I smite the
land of Egypt,
the pestilence with which the firstborn should be destroyed.

Exodus 12:13 In-Context

11 “These are your instructions for eating this meal: Be fully dressed, wear your sandals, and carry your walking stick in your hand. Eat the meal with urgency, for this is the LORD ’s Passover.

12 On that night I will pass through the land of Egypt and strike down every firstborn son and firstborn male animal in the land of Egypt. I will execute judgment against all the gods of Egypt, for I am the LORD !

13 But the blood on your doorposts will serve as a sign, marking the houses where you are staying. When I see the blood, I will pass over you. This plague of death will not touch you when I strike the land of Egypt.

14 “This is a day to remember. Each year, from generation to generation, you must celebrate it as a special festival to the LORD . This is a law for all time.

15 For seven days the bread you eat must be made without yeast. On the first day of the festival, remove every trace of yeast from your homes. Anyone who eats bread made with yeast during the seven days of the festival will be cut off from the community of Israel.