Amos is the book of the herdsman from Tekoa, a small town in Judah. He receives a direct call from God to prophesy against the unrighteousness of both Judah and Israel. Amos is the first prophet to proclaim that God is the ruler of the whole world.

Amos 5

5:12 For I know your manifold transgressions, and your mighty sins: they afflict the just, they take a bribe, and they turn aside the poor in the gate from their right.