the firstling: Heb. first born, etc. As these firstlings were the Lord's before, it would have been a solemn mockery to pretend to make them a matter of a singular vow; for they were already appointed, if clean, to be sacrificed.
which: Exo 13:2, Exo 13:12-13, Exo 22:30; Num 18:17; Deu 15:19