Exodus 23:14-16

14Three times thou shalt keep a feast unto me in the year.

15The feast of unleavened bread shalt thou keep: seven days thou shalt eat unleavened bread, as I commanded thee, at the time appointed in the month Abib (for in it thou camest out from Egypt); and none shall appear before me empty:

16and the feast of harvest, the firstfruits of thy labours, which thou sowest in the field: and the feast of ingathering, at the end of the year, when thou gatherest in thy labours out of the field.