Leviticus 23: 4-12

” ‘These are the Lord’s appointed feasts, the sacred assemblies you are to proclaim at their appointed times: The Lord’s Passover begins at twilight on the fourteenth day of the fist month. On the fifteenth day of that month the Lord’s Feast of Unleavened Bread begins; for seven days you must eat bread made without yeast. On the first day hold a sacred assembly and do no regular work. For seven days present an offering made to the Lord by fire. And on the seventh day hold a sacred assembly  and do no regular work.’ The Lord said to Moses, ‘ Speak to the Israelites and say to them: “When you enter the land I am going to give you and you reap its harvest, bring to the priest a sheaf of the first grain you harvest. He is to wave the sheaf before the Lord so it will be accepted on your behalf; the priest is to wave it on the day after the Sabbath. On the day you wave the sheaf, you must sacrifice as a burnt offering to the Lord a lamb a year old without defect.” ‘ “