Who was Joash in the Bible

Joash was a King of Judah who ruled at a very young age of 7. Under the counsel of Jehoiada his early years was marked with good deeds but after Jehoiada’s death he turned around to idolatry and even killed Zechariah who prophesied against his evil ways.

King Joash did not remember the kindness Zechariah’s father Jehoiada had shown him but killed his son. 2 CHRONICLES 24:22

King Joash of Judah should have paid more attention to the Lord’s words to Cain: “If you do not do what is right, sin is crouching at your door; it desires to have you, but you must master it” (Genesis 4:7).
Perhaps then he would not have turned so remarkably from good to bad during his reign.
The very fact that Joash was even alive to reign was a result of the gracious hand of God and the heroic acts of others. When he was just a baby, Joash’s father was murdered, and his grandmother saw this as her opportunity to rule Judah. She murdered the entire royal family her own grandchildren except for one: Joash. Jehosheba, a member of the royal family and the wife of a priest named Jehoiada, stole him away and hid Joash in the temple precincts for six years. Then Jehoiada arranged for the people to crown Joash king at seven years of age (2 Kings 11).
For the first part of Joash’s reign, Jehoiada remained an adviser to him, and he did what was pleasing to the Lord. He even arranged for the temple to be repaired. But once Jehoiada died, Joash began to listen to the officials of the land, who led him to worship idols. Later, Jehoiada’s son Zechariah prophesied against this wickedness, but Joash ordered that he be stoned to death. Because of his treacherous act toward Jehoiada’s son, Joash’s own officials killed him while he slept (2 Chronicles 24).
Athaliah, the daughter of wicked King Ahab of Israel, was the woman who tried to kill Joash along with all the royal family (see 2 Kings 8:26). Presumably her mother was Jezebel, Ahab’s idolatrous wife.