Leviticus 25:8

Thou shalt number seven sabbaths of years unto thee Besides the rest of the seventh year, God now appoints, as another perpetual ordinance, that every fiftieth year should be celebrated as an extraordinary year of rest, freedom, and rejoicing, of which public notice was to be given through the whole country, by sound of trumpet. On this year every ancient owner of lands and estates, that had been alienated by sale, was to be restored to his possession; and every Israelitish slave set at perfect liberty, to return to the family to which he belonged. So that how often soever an estate had been sold or alienated between one jubilee and another, or how many hands soever it had passed through, yet, in fifty years, or at the next jubilee, it must return to the heirs of the persons who were first possessed of it. All this was intended to shadow forth that true liberty from men's spiritual debts and slaveries which was to be purchased by Christ, and to be published to the world by the sound of the gospel.