What is written above? “And the Lord will pass over the door” (Exodus 12:23) – at that moment, as it were, He stood at the entrance.21Since God Himself was present, what need was there to put the sign of the blood on the lintel in order that the destroyer would not kill the Israelite firstborn? The way of the world is that, just as a slaughterer brings in his flock, and each lamb or sheep that he wants to slaughter, he takes red paint and marks it so he will recognize which to slaughter and which not to slaughter; so, “He will see the blood” (Exodus 12:23) – as it were, He stood at the entrance and repelled the destroyer so that it would not smite Israel.
God said to them: “You shall observe this matter as an ordinance for you and for your sons forever” (Exodus 12:24). Just as I did for you now, so I am destined to do for you in the future, as it is stated: “For, behold, the day comes, it burns as a furnace, [and all the proud, and all who perform evil, will be stubble; and the day that comes will set them ablaze…]” (Malachi 3:19), but you, “I will have mercy on them, as a man has mercy on his son” (Malachi 3:17).