Exodus 23:15-17 New Revised Standard Version Catholic Edition (NRSVCE)
15 You shall observe the festival of unleavened bread; as I commanded you, you shall eat unleavened bread for seven days at the appointed time in the month of Abib, for in it you came out of Egypt.
No one shall appear before me empty-handed.
16 You shall observe the festival of harvest, of the first fruits of your labor, of what you sow in the field. You shall observe the festival of ingathering at the end of the year, when you gather in from the field the fruit of your labor. 17 Three times in the year all your males shall appear before the Lord God.