Deuteronomy 16:1-17

“Observe the month of Abib, and keep the Passover to the LORD your God, for in the month of Abib the LORD your God brought you out of Egypt by night. Therefore you shall sacrifice the Passover to the LORD your God, from the flock and the herd, in the place where the LORD chooses to put His name. You shall eat no leavened bread with it; seven days you shall eat unleavened bread with it, that is, the bread of affliction (for you came out of the land of Egypt in haste), that you may remember the day in which you came out of the land of Egypt all the days of your life. And no leaven shall be seen among you in all your territory for seven days, nor shall any of the meat which you sacrifice the first day at twilight remain overnight until morning. “You may not sacrifice the Passover within any of your gates which the LORD your God gives you; but at the place where the LORD your God chooses to make His name abide, there you shall sacrifice the Passover at twilight, at the going down of the sun, at the time you came out of Egypt. And you shall roast and eat it in the place which the LORD your God chooses, and in the morning you shall turn and go to your tents. Six days you shall eat unleavened bread, and on the seventh day there shall be a sacred assembly to the LORD your God. You shall do no work on it. “You shall count seven weeks for yourself; begin to count the seven weeks from the time you begin to put the sickle to the grain. Then you shall keep the Feast of Weeks to the LORD your God with the tribute of a freewill offering from your hand, which you shall give as the LORD your God blesses you. You shall rejoice before the LORD your God, you and your son and your daughter, your male servant and your female servant, the Levite who is within your gates, the stranger and the fatherless and the widow who are among you, at the place where the LORD your God chooses to make His name abide. And you shall remember that you were a slave in Egypt, and you shall be careful to observe these statutes. “You shall observe the Feast of Tabernacles seven days, when you have gathered from your threshing floor and from your winepress. And you shall rejoice in your feast, you and your son and your daughter, your male servant and your female servant and the Levite, the stranger and the fatherless and the widow, who are within your gates. Seven days you shall keep a sacred feast to the LORD your God in the place which the LORD chooses, because the LORD your God will bless you in all your produce and in all the work of your hands, so that you surely rejoice. “Three times a year all your males shall appear before the LORD your God in the place which He chooses: at the Feast of Unleavened Bread, at the Feast of Weeks, and at the Feast of Tabernacles; and they shall not appear before the LORD empty-handed. Every man shall give as he is able, according to the blessing of the LORD your God which He has given you.