Exodus 34:22-26

You shall observe the Feast of Weeks, the firstfruits of wheat harvest, and the Feast of Ingathering at the year’s end. Three times in the year shall all your males appear before the LORD God, the God of Israel. For I will cast out nations before you and enlarge your borders; no one shall covet your land, when you go up to appear before the LORD your God three times in the year. “You shall not offer the blood of my sacrifice with anything leavened, or let the sacrifice of the Feast of the Passover remain until the morning. The best of the firstfruits of your ground you shall bring to the house of the LORD your God. You shall not boil a young goat in its mother’s milk.”