'Firstling' in the Bible

that thou shalt set apart unto Jehovah all that openeth the womb, and every firstling which thou hast that cometh of a beast; the males shall be Jehovah's.

And every firstling of an ass thou shalt redeem with a lamb; and if thou wilt not redeem it, then thou shalt break its neck: and all the first-born of man among thy sons shalt thou redeem.

And the firstling of an ass thou shalt redeem with a lamb: and if thou wilt not redeem it, then thou shalt break its neck. All the first-born of thy sons thou shalt redeem. And none shall appear before me empty.