Leviticus 25:8-10

8“‘You must count off seven weeks of years, seven times seven years, and the days of the seven weeks of years will amount to forty-nine years.

9You must sound loud horn blasts – in the seventh month, on the tenth day of the month, on the Day of Atonement – you must sound the horn in your entire land.

10So you must consecrate the fiftieth year, and you must proclaim a release in the land for all its inhabitants. That year will be your jubilee; each one of you must return to his property and each one of you must return to his clan.