Exodus 34:19-21

All that openeth the matrix {is} mine; and every firstling among thy cattle, {whether} ox or sheep, {that is male}. {sheep: or, kid} But the firstling of an ass thou shalt redeem with a lamb: and if thou redeem {him} not, then shalt thou break his neck. All the firstborn of thy sons thou shalt redeem. And none shall appear before me empty. {lamb: or, kid} Six days thou shalt work, but on the seventh day thou shalt rest: in earing time and in harvest thou shalt rest.