The following account is recorded in the Holy Scripture in the first book of Samuel chapter 15. 

Requirement: of God for Saul, the appointed king of Israel was to utterly destroy the sinners (Amalekites, led by king Agag) and everything that belonged to them. No one (including their livestock) was to be spared.
Response: of Saul, the appointed king of Israel was not total obedience; He spared king Agag and the best of the land.
Reason: that Saul gave was that he wished to sacrifice what he had spared as an offering to the LORD.
Result: of Saul’s action was rejection. God rejected Saul from continuing to be the king of Israel.

Though Saul’s reason sounds superficially as a good reason, but in reality it was not. Why, God wanted to completely (utterly) destroy sin and avenge His people. But the appointed king (Saul), disappointed the King of kings by not totally obeying God’s commandment (requirement). To OBEY is better than sacrifice!

Point(s) to ponder:
1. What may seem like a good reason (even if it is about sacrificing and worshipping God) can be unacceptable if it contradicts what God has commanded us to.
2. Disobedience (even partial disobedience) can lead to total rejection from God.
3. Total obedience is better than any sacrifice we can give to God.

1 Samuel 15:22 (KJV)
22 And Samuel said, Hath the LORD as great delight in burnt offerings and sacrifices, as in obeying the voice of the LORD? Behold, to obey is better than sacrifice, and to hearken than the fat of rams.