Leviticus 23:9

6 On the fifteenth day of the same month is the feast of unleavened bread to Yahweh: seven days you shall eat unleavened bread.

7 In the first day you shall have a holy convocation: you shall do no servile work.

8 But you shall offer an offering made by fire to Yahweh seven days: in the seventh day is a holy convocation; you shall do no servile work.

10 Speak to the children of Israel, and tell them, When you are come into the land which I give to you, and shall reap the harvest of it, then you shall bring the sheaf of the first-fruits of your harvest to the priest:

11 and he shall wave the sheaf before Yahweh, to be accepted for you: on the next day after the Sabbath the priest shall wave it.

12 In the day when you wave the sheaf, you shall offer a he-lamb without blemish a year old for a burnt offering to Yahweh.