(as it is written in the Law of the Lord, “Every firstborn male that opens the womb shall be called holy [set apart and dedicated] to the Lord)” [Ex 13:1, 2, 12; Num 8:17]
“Sanctify to Me [that is, set apart for My purpose] every firstborn, the first offspring of every womb among the children of Israel, both of man and of animal; it is Mine.”
“You shall not delay the offering from your harvest and your vintage. You shall give (consecrate, dedicate) to Me the firstborn of your sons. [Ex 34:19, 20]
Every firstborn of the womb of all flesh, whether it is man or animal, which they bring to the Lord, shall be yours; nevertheless, the firstborn of man you shall most certainly redeem, and the firstborn of unclean animals you shall redeem.
for all the firstborn are Mine. On the day that I killed all the firstborn in the land of Egypt, I consecrated for Myself all the firstborn in Israel, both man and animal. They shall be mine; I am the Lord.”