'Day of Atonement' in the Bible

"However on the tenth day of this seventh month is the day of atonement: it shall be a holy convocation to you, and you shall afflict yourselves; and you shall offer an offering made by fire to the LORD.

You shall do no manner of work in that same day; for it is a day of atonement, to make atonement for you before the LORD your God.

Then you shall sound the loud trumpet on the tenth day of the seventh month. On the Day of Atonement you shall sound the trumpet throughout all your land.