Leviticus 23:10-11

10 Speak to the children of Israel, and say to them, When you be come into the land which I give to you, and shall reap the harvest thereof, then you shall bring a sheaf of the first fruits of your harvest to the priest:

11 And he shall wave the sheaf before the LORD, to be accepted for you: on the morrow after the sabbath the priest shall wave it.