Exodus 34:21 in the King James Version
Six days thou shalt work, but on the seventh day thou shalt rest: in earing time and in harvest thou shalt rest.
Context
20 You shall redeem the firstborn of a donkey with a lamb. If you will not redeem it, then you shall break its neck. You shall redeem all the firstborn of your sons. No one shall appear before me empty.
21 “Six days you shall work, but on the seventh day you shall rest: in plowing time and in harvest you shall rest.
22 “You shall observe the feast of weeks with the first fruits of wheat harvest, and the feast of harvest at the year’s end.