Exodus 23:14-17

14 aThree times in the year you shall keep a feast to me. 15 bYou shall keep the Feast of Unleavened Bread. As I commanded you, you shall eat unleavened bread for seven days at the appointed time in the month of cAbib, for in it you came out of Egypt. dNone shall appear before me empty-handed. 16You shall keep ethe Feast of Harvest, of the firstfruits of your labor, of what you sow in the field. You shall keep the fFeast of Ingathering at the end of the year, when you gather in from the field the fruit of your labor. 17 gThree times in the year shall all your males appear before the Lord God.

Deuteronomy 16:16

16 hThree times a year all your males shall appear before the Lord your God at the place that he will choose: at the Feast of Unleavened Bread, at the Feast of Weeks, and at the Feast of Booths. iThey shall not appear before the Lord empty-handed.
Copyright information for ESV