Exodus 23:16, 19

Also [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.

“You shall bring the choice first fruits of your ground into the house of the LORD your God. “ Y ou shall not boil a young goat in its mother’s milk.