Leviticus 23:9-12

And the LORD spoke to Moses, saying, “Speak to the people of Israel and say to them, When you come into the land that I give you and reap its harvest, you shall bring the sheaf of the firstfruits of your harvest to the priest, and he shall wave the sheaf before the LORD, so that you may be accepted. On the day after the Sabbath the priest shall wave it. And on the day when you wave the sheaf, you shall offer a male lamb a year old without blemish as a burnt offering to the LORD.