Exodus 23:14-17

23:14 “Three times in the year you must make a pilgrim feast to me. 23:15 You are to observe the Feast of Unleavened Bread; seven days you must eat bread made without yeast, as I commanded you, at the appointed time of the month of Abib, for at that time you came out of Egypt. No one may appear before me empty-handed.

23:16 “You are also to observe the Feast of Harvest, the firstfruits of your labors that you have sown in the field, and the Feast of Ingathering at the end of the year when you have gathered in your harvest out of the field. 23:17 At three times in the year all your males will appear before the Lord God.