Numbers 18:15

15. Every thing that openeth the matrix Every firstborn male. The female firstborn of man and beast were exempted from consecration. See Leviticus 27:26, note. The firstborn of man were to be consecrated to Jehovah as a sacrifice, not after the manner of the heathen, by slaying and burning upon the altar, but by presenting them to the Lord as living sacrifices, devoting all their powers of body and mind to his service. Romans 12:1, note. “As the Egyptians were judged in their firstborn children because of their guilt, so that the children took the place of the whole nation, and bore as a sacrifice the curse of extermination which lay on all; so, on the contrary, Israel the people chosen by Jehovah and redeemed from the bondage of man in testimony that it owes its existence and possessions to divine grace alone,… shall bring to God, as payment, the firstling blessings of his house in place of the whole.” Oehler. Since the first birth represented all the births, the whole nation was to consecrate itself to Jehovah, and present itself as a priestly nation in the consecration of the firstborn, thus fore-shadowing the “royal priesthood” of every individual believer in Christ. See the Septuagint of Exodus 19:6, and 1 Peter 2:9.