Exodus 34:19-21

Young's Literal Translation

¹⁹ `All opening a womb [are] Mine, and every firstling of thy cattle born a male, ox or sheep;

²⁰ and the firstling of an ass thou dost ransom with a lamb; and if thou dost not ransom, then thou hast beheaded it; every first-born of thy sons thou dost ransom, and they do not appear before Me empty.

²¹ `Six days thou dost work, and on the seventh day thou dost rest; in ploughing-time and in harvest thou dost rest.