Leviticus 23:9-11

And the LORD spoke to Moses, saying, “Speak to the children of Israel, and say to them: ‘When you come into the land which I give to you, and reap its harvest, then you shall bring a sheaf of the firstfruits of your harvest to the priest. He shall wave the sheaf before the LORD, to be accepted on your behalf; on the day after the Sabbath the priest shall wave it.