To obey is better than sacrifice, and to heed is better than the fat of rams

1 Samuel 15:1-35
Then the word of the Lord came to Samuel: “I regret that I have made Saul king, because he has turned away from me and has not carried out my instructions.” Samuel was angry, and he cried out to the Lord all that night.
Samuel said, “Although you were once small in your own eyes, did you not become the head of the tribes of Israel? The Lord anointed you king over Israel.  Why did you not obey the Lord? Why did you pounce on the plunder and do evil in the eyes of the Lord?
“Does the Lord delight in burnt offerings and sacrifices as much as in obeying the Lord? To obey is better than sacrifice,  and to heed is better than the fat of rams.
23 For rebellion is like the sin of divination,  and arrogance like the evil of idolatry. Because you have rejected the word of the Lord,  he has rejected you as king.”
He who is the Glory of Israel does not lie or change his mind; for he is not a human being, that he should change his mind.
This time Saul's disobedience is deliberate. He is rejected by God as king, and Samuel pays him no more official visits. The prophet had foreseen trouble, He might well have relished Saul's downfall. instead, he went home grieving.
Why?
God's word can not be changed or modified to obeying God's word is more important than sacrifices.
Rebellion is sin like the evil of idolatry. So Saul has totally disobeyed God's instruction.
Saul forgot he was small and is the Lord raised him as king of Israel.
Saul's victory is because of God's blessing.
God regrets that he has made Saul king, for Saul turned away from God, so the authority and glory may let people forget the grace of the Lord.
How?
Be humble and obey the word of the Lord, for the victory and salvation is come from the Lord. There is no other way.