King Amaziah led the people of Judah in a battle against Edom and emerged victorious. After that, He picked a fight with the people of Israel. Here is the account:
Then Amaziah sent messengers to Jehoash the son of Jehoahaz, son of Jehu, king of Israel, saying, “Come, let us look one another in the face.” And Jehoash king of Israel sent word to Amaziah king of Judah, “A thistle on Lebanon sent to a cedar on Lebanon, saying, ‘Give your daughter to my son for a wife,’ and a wild beast of Lebanon passed by and trampled down the thistle. You have indeed struck down Edom, and your heart has lifted you up. Be content with your glory, and stay at home, for why should you provoke trouble so that you fall, you and Judah with you?”
In other words, Amaziah got in Jehoash’s face (who is not to be confused with King Jehoash of Judah, Amaziah’s father) and Jehoash said, “you don’t want to mess with me.” Jehoash was right. Amaziah fought against Israel and was defeated.
Even though he followed God as his father had done, Amaziah forgot who supplied him with strength to win battles, and his defeat at the hands of an evil king was a hard lesson. We are weak and frail, and our strength is only supplied by the Lord. He saves us and sustains and breathes life into us. Let us not forget His grace toward us, and let us trust in Him alone, for He alone is trustworthy and faithful.