Saul said to Samuel, Yes, I have obeyed the voice of Yahweh, and have gone the way which Yahweh sent me, and have brought Agag the king of Amalek, and have utterly destroyed the Amalekites.
Saul’s lack of submission was an even more serious sin than David’s sins of murder and adultery. God did not remove the kingship from David for his sins, but He did from Saul.