Leviticus 23:23-25

Again the LORD spoke to Moses, saying, “Say to the children of Israel, ‘On the first day of the seventh month (almost October), you shall observe a day of solemn sabbatical rest, a memorial day announced by the blowing of trumpets, a holy convocation. You shall not do any laborious work [on that day], but you shall present an offering by fire to the LORD.’ ”