In Psalms, chapter eighty-nine, verse thirty, God’s promises in verses thirty through thirty-seven did not ensure the reign of David’s descendants as kings forever, nor did they address the issue of the personal salvation of these kings. However, the promises were given to David to assure Him that the unfaithfulness of Israel and her kings would not interfere with God’s purpose to establish one of his descendants, Jesus Christ, upon an everlasting throne.
God, for the sake of David, found a man after His own heart. However, the descendants of the servant of God were not like him. Therefore, the Lord would not establish them forever. The king before David, King Saul, has a description of him in First Samuel nine, verse two, “And he had a son, whose name was Saul, a choice young man, and a goodly: and there was not among the children of Israel a goodlier person than he: from his shoulders and upward he was higher than any of the people.” However, it is the inside where the heart is, is what God sees and knows all about.
Saul did not follow God’s full instructions or live godly, as spoken through Samuel, a servant of God, as in First Samuel thirteen, verses eleven to fourteen.
In a family, the parents are the head of the household, which relates to the king as the leader. Although the head serves God and applies godly principles to the younger siblings, it does not always translate into them serving God. Each person within the family will have to live their life, and hopefully, based on what they learn from their parents from the godly perspective, they will accept God and His will on their own. Parents cannot save their children. Only God can do that with them accepting Him by receiving salvation.