Leviticus 23:20-27
English Standard Version
Chapter 23
20And the priest shall wave them with the bread of the firstfruits as a wave offering before the Lord, with the two lambs. They shall be holy to the Lord for the priest. 21And you shall make a proclamation on the same day. You shall hold a holy convocation. You shall not do any ordinary work. It is a statute forever in all your dwelling places throughout your generations.
23And the Lord spoke to Moses, saying,
24"Speak to the people of Israel, saying, In the seventh month, on the first day of the month, you shall observe a day of solemn rest, a memorial proclaimed with blast of trumpets, a holy convocation.
25You shall not do any ordinary work, and you shall present a food offering to the Lord."