Hosea is the first book of the twelve minor prophets. Because the times are outwardly prosperous, idolatry prevails and immorality is rampant. Hosea urges a return to God in order that He may show mercy and forgiveness.

Hosea 4

4:13 They sacrifice upon the tops of the mountains, and burn incense upon the hills, under oaks and poplars and elms, because the shadow thereof is good: therefore your daughters shall commit whoredom, and your spouses shall commit adultery.