Though David would eventually be appointed as the king to replace Saul, he was not specified at this point in time. In his answer to Saul, Samuel was emphasizing that the Lord wanted a king who kept his commandments.1 In contrast with the king that God wanted, Saul had panicked in the face of overwhelming odds and failed to recall moments of past deliverance. He was not a model of obedience and godly behaviour in the midst of fear (cf. Deuteronomy 17:18–20; Psalm 101:1–8).2
14 But now your kingdom shall not continue. The LORD has sought out a man after his own heart, and the LORD has commanded him to be prince over his people, because you have not kept what the LORD commanded you.”