Numbers 28:26

On the day of firstfruits, when you present an offering of new grain to the Lord during the Feast of Weeks, you are to hold a sacred assembly; you must not do any regular work.

Note That is, Shavuot, the late spring feast of pilgrimage to Jerusalem; it is also known as the Feast of Harvest (see Exodus 23:16) or the Feast of Pentecost (see Acts 2:1).

Also in the day of the firstfruits, when ye bring a new meat offering unto the Lord, after your weeks be out, ye shall have an holy convocation; ye shall do no servile work:

“‘Also in the day of the first fruits, when you offer a new meal offering to the Lord in your feast of weeks, you shall have a holy convocation. You shall do no regular work;

Also in the day of the first-fruits, when ye offer a new meal-offering unto Jehovah in your feast of weeks, ye shall have a holy convocation; ye shall do no servile work;