Leviticus 23:24, 39

“Speak to the sons of Israel, saying, ‘In the seventh month on the first of the month you shall have a rest, a reminder by blowing of trumpets, a holy convocation.

‘On exactly the fifteenth day of the seventh month, when you have gathered in the crops of the land, you shall celebrate the feast of the LORD for seven days, with a rest on the first day and a rest on the eighth day.