'Day of Atonement' in the Bible

“On exactly the tenth day of this seventh month is the day of atonement; it shall be a holy convocation for you, and you shall humble your souls and present an offering by fire to the Lord.

You shall not do any work on this same day, for it is a day of atonement, to make atonement on your behalf before the Lord your God.

You shall then sound a ram’s horn abroad on the tenth day of the seventh month; on the day of atonement you shall sound a horn all through your land.