In the lives of Jehoshaphat, king of Judah, and Ahaziah, king of Israel, we see what made Jehoshaphat, a wise son, and what made Ahaziah, a foolish son.  Jehoshaphat was a wise son in that he was focused in doing the right thing before the Lord.  Jehoshaphat was a peacemaker, a warrior and a moral person.  Jehoshaphat provided security for his people and he learned from his mistakes. Ahaziah, on the other hand, took after Ahab, his father, Jezebel, his mother, and Jeroboam, the son of Nebat.

Other passages: 1 Kings 15:8-14; Deuteronomy 12:1-14; Psalm 139:23-24; Matthew 5:9; 2 Chronicles 20:35-37