Deuteronomy 16:1-17

“Observe the month of Abib and celebrate the Passover to the LORD your God, for in the month of Abib the LORD your God brought you out of Egypt by night. You shall sacrifice the Passover [lamb] to the LORD your God from the flock or the herd, in the place where the LORD chooses to establish His Name (Presence). You shall not eat leavened bread with it; instead, for seven days you shall eat the Passover with unleavened bread, the bread of affliction (for you left the land of Egypt in haste); [do this] so that all the days of your life you may remember [thoughtfully] the day when you came out of the land of Egypt. For seven days no leaven shall be seen with you in all your territory, and none of the meat which you sacrificed the evening of the first day shall remain overnight until morning. You are not allowed to sacrifice the Passover [lamb] in any of your cities which the LORD your God is giving you; but at the place where the LORD your God chooses to establish His Name (Presence), you shall sacrifice the Passover [lamb] in the evening at sunset, at the time that you came out of Egypt. You shall cook and eat it in the place which the LORD your God chooses. In the morning you are to return to your tents. For six days you shall eat unleavened bread, and on the seventh day there shall be a celebration to the LORD your God; so you shall do no work [on that day]. “You shall count seven weeks for yourself; you shall begin to count seven weeks from the time you first put the sickle to the standing grain. Then you shall celebrate the Feast of Weeks to the LORD your God with a tribute of a freewill offering from your hand, which you shall give [to Him] just as the LORD your God blesses you; and you shall rejoice before the LORD your God, you and your son and your daughter and your male and female servants and the Levite who is within your [city] gates, and the stranger and the orphan and the widow who are among you, at the place where the LORD your God chooses to establish His Name (Presence). You shall remember that you were a slave in Egypt, and you shall be careful to obey these statutes. “You shall celebrate the Feast of Booths (Tabernacles) seven days, when you have gathered in [the grain] from your threshing floor and [the wine] from your wine vat. You shall rejoice in your feast, you and your son and your daughter and your male and female servants and the Levite and the stranger and the orphan and the widow who are within your city. Seven days you shall celebrate a 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 will be altogether joyful. “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 (Passover) and at the Feast of Weeks (Pentecost) and at the Feast of Booths (Tabernacles), and they shall not appear before the LORD empty-handed. Every man shall give as he is able, in accordance with the blessing which the LORD your God has given you.