Samuel said to Saul, I will not return with you; for you have rejected the word of Yahweh, and Yahweh has rejected you from being king over Israel.
Saul had formerly been genuinely humble. He had realistically evaluated himself before his anointing (1 Samuel 14:17; cf. 1 Samuel 9:21). Yet when he became king he viewed himself as the ultimate authority in Israel, a view common among ancient Near Eastern monarchs. This attitude led him to disobey the Law of God. God had sent Saul on a mission (1 Samuel 14:18; cf. Matthew 28:19-20), which involved the total extermination of the Amalekites. The Hebrew word translated "sinners" means habitually wicked people (cf. Psalms 1:1; Psalms 1:5), like the Canaanites.