Leviticus 23:24, 39

“Tell the people of Israel: ‘On the first day of the seventh month you must have a special day of rest, a holy meeting, when you blow the trumpet for a special time of remembering.

“ ‘So on the fifteenth day of the seventh month, after you have gathered in the crops of the land, celebrate the LORD’s festival for seven days. You must rest on the first day and the eighth day.