Deuteronomy 16:1, 10, 13

Celebrate the Passover of the LORD your God during the month of Abib, because it was during Abib that he brought you out of Egypt at night.

and then celebrate the Feast of Weeks for the LORD your God. Bring an offering as a special gift to him, giving to him just as he has blessed you.

Celebrate the Feast of Shelters for seven days, after you have gathered your harvest from the threshing floor and winepress.