Leviticus 23:7

4 These are the fixed feasts of the Lord, the holy days of worship which you will keep at their regular times.

5 In the first month, on the fourteenth day of the month at nightfall, is the Lord's Passover;

6 And on the fifteenth day of the same month is the feast of unleavened bread; for seven days let your food be unleavened bread.

7 On the first day you will have a holy meeting; you may do no sort of field-work.

8 And every day for seven days you will give a burned offering to the Lord; and on the seventh day there will be a holy meeting; you may do no field-work.

9 And the Lord said to Moses,

10 Say to the children of Israel, When you have come to the land which I will give you, and have got in the grain from its fields, take some of the first-fruits of the grain to the priest;