Then you shall cause the trumpet of the Jubilee to sound on the tenth day of the seventh month; on the Day of Atonement you shall make the trumpet to sound throughout all your land.
Leviticus 25:9
Surrounding context
25:8 "And you shall count seven sabbaths of years for yourself, seven times seven years; and the time of the seven sabbaths of years shall be to you forty-nine years.
25:9 Then you shall cause the trumpet of the Jubilee to sound on the tenth day of the seventh month; on the Day of Atonement you shall make the trumpet to sound throughout all your land.
25:10 And you shall consecrate the fiftieth year, and proclaim liberty throughout all the land to all its inhabitants. It shall be a Jubilee for you; and each of you shall return to his possession, and each of you shall return to his family.