Exodus 34:23

21Six days thou shalt work, but on the seventh day thou shalt rest: in earing time and in harvest thou shalt rest.

22And thou shalt observe the feast of weeks, of the firstfruits of wheat harvest, and the feast of ingathering at the year’s end.

23Thrice in the year shall all your menchildren appear before the LORD God, the God of Israel.

24For I will cast out the nations before thee, and enlarge thy borders: neither shall any man desire thy land, when thou shalt go up to appear before the LORD thy God thrice in the year.

25Thou shalt not offer the blood of my sacrifice with leaven; neither shall the sacrifice of the feast of the passover be left unto the morning.