Exodus 34:22-26

22You shall observe and celebrate the Feast of Weeks (Harvest, First Fruits, or Pentecost), the first fruits of the wheat harvest, and the Feast of Ingathering (Booths or Tabernacles) at the year’s end.

23Three times a year all your males shall appear before the Lord God, the God of Israel.

24For I will drive out and dispossess nations before you and enlarge your borders; nor shall any man covet (actively seek for himself) your land when you go up to appear before the Lord your God three times a year.

25“You shall not offer the blood of My sacrifice with leavened bread, nor shall the sacrifice of the Feast of the Passover (Unleavened Bread) be left over until morning.

26“You shall bring the very first of the first fruits of your ground to the house of the Lord your God. “You shall not boil a young goat in his mother’s milk [as some pagans do].”