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

5:3 For thus saith the Lord GOD; The city that went out by a thousand shall leave an hundred, and that which went forth by an hundred shall leave ten, to the house of Israel.