Tosefta zu Michah 3:12

[With respect to] Kohanim and Levites who were assisting between threshing floors, [the landowners should] not give them Terumah and tithes [as part of] their salary, and if they gave them, behold, they are [deemed] unconsecrated [produce], as it is said (Num. 18:32), "and you shall not profane the sacred donations of the Children of Israel," [and treated as though] they were already unconsecrated. And it is said (Mal. 2:8), "You corrupted the covenant of the Levites, said the Lord of Hosts." More than this, they (i.e., the Sages) said, "Their Terumah is not Terumah and their tithes are not tithes," and not only that, but the Sages [also] sought to punish them such that they would need to separate Terumah from their own produce. And about them it is written, saying (Micah 3:11, JPS tr.), "Her rulers judge for gifts, Her priests give rulings for a fee, [And her prophets divine for pay]," and therefore God brought on them three punishments corresponding to their three sins that they committed, as it is said (Micah 3:12, JPS tr.), "Assuredly, because of you, Zion shall be plowed as a field, [And Jerusalem shall become heaps of ruins, And the Temple Mount a shrine in the woods]."