Exodus 23:14-16

14“Three times a year you shall celebrate a feast [dedicated] to Me.

15You shall observe the Feast of Unleavened Bread; for seven days you shall eat unleavened bread, as I commanded you, 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 [but you shall bring sacrificial offerings].

16Also [you shall observe] the Feast of Harvest (Weeks, Pentecost, or First Fruits), acknowledging the first fruits of your labor, of what you sow in the field. And [third] the Feast of Ingathering (Booths or Tabernacles) at the end of the year when you gather in [the fruit of] your labors from the field.