Exodus 23:14-16

14“Celebrate a festival in my honor three times a year.

15Observe the Festival of Unleavened Bread. As I commanded you, you are to eat unleavened bread for seven days at the appointed time in the month of Abib, because you came out of Egypt in that month. No one is to appear before me empty-handed.

16Also observe the Festival of Harvest with the firstfruits of your produce from what you sow in the field, and observe the Festival of Ingathering at the end of the year, when you gather your produce from the field.