The Omniscience of God - 1 Samuel 13:13-14

1 Samuel 13:13-14 You acted foolishly," Samuel said. "You have not kept the command the LORD your God gave you; if you had, he would have established your kingdom over Israel for all time. But now your kingdom will not endure; the LORD has sought out a man after his own heart and appointed him leader of his people, because you have not kept the LORD's command."

Genesis 49:10 The scepter will not depart from Judah, nor the rulers staff from between his feet, until he comes to whom it belongs and the obedience of the nations is his.

God always acts the same way toward moral evil and the same way toward moral good. In his every reaction to men's responses to him, the immutable moral fixity of his character is evident. If men and women alter their relations to him, he will always respond in a manner consistent with his immutable holy character. This being true, God does not deem it necessary to attach to every promise he makes or to every prediction of judgment he issues the conditions for human weal or woe. They are always to be understood as in force, though they may be unstated. They are always operative so that whatever men do, God responds accordingly. And if the biblical interpreter does not realize this - that these conditions are operative even though unstated - he may conclude that God has broken a promise or has failed to carry out a predicted judgment.

Faithfulness and covenant loyalty were stipulations in the promises of God to Saul. Saul was rejected for various reasons. But, God knew the end from the beginning (Isa. 46:9-10) and all possible outcomes of every situation. Israel had been previously warned about kings like Saul (1 Sam. 8:7-21; Prov. 21:1). Therefore, Samuel was correct in saying, "Saul if you had been faithful, God would have done... " However, Saul was never a man after God's own heart.

Reference

Reymond, Robert L. A New Systematic Theology of the Christian Faith. Nashville: Thomas Nelson, Inc. 1998, (181)