What does the Bible say about the calling of David as king?

In 1 Samuel 16, God instructs the prophet Samuel to anoint David as king, indicating that David was chosen according to God's purpose and plan long before he assumed the throne. This act underscores the doctrine of God's sovereign election, illustrating that God's choice is not based on human merit or public opinion, but solely on His divine will. David's journey reflects the reality that God's chosen ones often face trials and rejection before their exaltation, similar to the persecution of Jesus, God's ultimate chosen King.