Nahum is the sequel to Jonah

Nineveh was a wicked city, but God had mercy on her in Jonah; he would not leave the guilty unpunished in Nahum.   "God opposes the proud, but gives grace to the humble." Mercy on the oppressed is often judgment on their oppressors.   Who was Nahum and who did he write to and why?  Nineveh is the common denominator between Jonah and Nahum, but there is a lot of difference in how the books are written.