Saul was a king "whom you (Israel) have chosen for yourselves" (1 Samuel 8:18; NKJV).
David, in contrast, was "a man after His (Jehovah) own heart" (1 Samuel 13:14; NKJV).
Question: What was the difference between Israel's choice and Jehovah's choice?
Answer: But the LORD said to Samuel,"Do not look at his appearance or at his physical stature, because I have refused him. For the LORD does not see as man sees; for man looks at the outward appearance, but the LORD looks at the heart" (1 Samuel 16:7; NKJV).
Jason Cicero