'Day of Atonement' in the Bible

Also on the tenth day of this seventh month there shall be a day of atonement; it shall be a holy convocation to you, and ye shall afflict your souls, and offer an offering made by fire to the LORD.

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

Then shalt thou cause the trumpet of the jubilee to sound, on the tenth day of the seventh month, in the day of atonement shall ye make the trumpet sound throughout all your land.