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.
Jewish Publication Society of America Version (JPS1917) - Numbers 28:26 >Also in the day of the first-fruits, when ye bring a new meal-offering unto the LORD in your feast of weeks, ye shall have a holy convocation: ye shall do no manner of servile work;