And when Pharaoh stubbornly refused to let us go, the LORD killed every firstborn in the land of Egypt, both of man and beast. This is why I sacrifice to the LORD the firstborn male of every womb, but I redeem all the firstborn of my sons.’
Here we have, I. Further directions concerning the dedicating of their firstborn to God. 1. The firstlings of their cattle were to be dedicated to God, as part of their possessions. Those of clean beasts - calves, lambs, and kids - if males, were to be sacrificed, Exo 22:30; Num 18:17, Num 18:18.
Commenting on Exodus 13:11-16
And it came to pass, when Pharaoh would hardly let us go,.... Showed great reluctance to it, and with difficulty was prevailed upon to dismiss them: that the Lord slew all the firstborn in the land of Egypt, both the firstborn of men, and the firstborn of beast: which he did in one night, making use of a destroying angel or angels for that purpose...
Exo 13:15-16 לשׁלּחנוּ הקשׁה: “he made hard” (sc., his heart, cf. Exo 7:3) “to let us go.” The sanctification of the first-born is enforced in Exo 13:16 in the same terms as the keeping of the feast of Mazzoth in Exo 13:9, with this exception, that instead of לזכרון we have לטוטפת, as in Deu 6:8, and Deu 11:18.
Commenting on Exodus 13:15-16