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

5:16 Therefore the LORD, the God of hosts, the Lord, saith thus; Wailing shall be in all streets; and they shall say in all the highways, Alas! alas! and they shall call the husbandman to mourning, and such as are skilful of lamentation to wailing.