tn The form הַכֹּתִי (hakkoti) is the Hiphil infinitive construct of the verb נָכָה (nakhah, “to strike, smite, attack”). Here, after the idiomatic “in the day of,” the form functions in an adverbial clause of time—“when I destroyed.”

sn In the Exodus event of the Passover night the principle of substitution was presented. The firstborn child was redeemed by the blood of the Lamb and so belonged to God, but then God chose the Levites to serve in the place of the firstborn. The ritual of consecrating the firstborn son to the Lord was nevertheless carried out, even with Jesus, the firstborn son of Mary (Luke 2:22–23).