Leviticus 16:29-30

“This shall be a permanent statute for you: in the seventh month (nearly October) on the tenth day of the month you shall humble yourselves [by fasting] and not do any work, whether the native-born or the stranger who lives temporarily among you; for it is on this day that atonement shall be made for you, to cleanse you; you will be clean from all your sins before the LORD. [Heb 10:1, 2; 1 John 1:7, 9]