Leviticus 23:8, 12, 36

But you shall present a food offering to the LORD for seven days. On the seventh day is a holy convocation; you shall not do any ordinary work.”

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.

For seven days you shall present food offerings to the LORD. On the eighth day you shall hold a holy convocation and present a food offering to the LORD. It is a solemn assembly; you shall not do any ordinary work.