Old Testament

Exodus 13:1-2,12
Instructions for Remembering the Passover
131The Lord spoke to Moses: 2“Set apart all the firstborn for me, the firstborn of every mother[] among the Israelites, both people and animals. The firstborn belongs to me.”
12then you must dedicate the firstborn of every mother to the Lord. Every firstborn of your livestock, the ones that are males, will belong to the Lord.

Footnotes

  • 13:2 Literally the opener of every womb. Jewish tradition, however, focuses more on the firstborn sons of fathers. This verse seems to be a general statement of a principle, for which details are given later. It is not clear how the principle was to be applied to flocks.