Leviticus 25:9

The year of Jubile began on the tenth of the seventh month and was proclaimed by the sound of the trumpet. The coincidence of this ceremony with the Day of Atonement presents a difficulty to some commentators, but according to Ezekiel 40:1 the tenth day of the month is sometimes reckoned as the first day of the year. Others would regard the words -in the day of atonement" as a later insertion. Dillmann sees nothing incongruous in the trumpet sound on the Day of Atonement, and considers the reconciliation of that day as an appropriate beginning of a year in which each one acquired his liberty. Restoration to God's favour was the preliminary to entering upon his possession. Another explanation of the text is that the trumpet sound was a note of preparation six months before the actual commencement of the Jubile in the spring but the ceremony seems intended to usher in the actual year, and was coincident with the proclamation of liberty.