What does 1 Samuel 15:33 mean?

Samuel is appearing "before the Lord" and in the presence of the elders of Israel (1 Samuel 15:30–31). He has called for Agag (1 Samuel 15:32), the king whom Saul failed to kill as instructed by the Lord (1 Samuel 15:3). Agag assumes that he is safe and that the killing is done. Instead, Samuel explains why God's sentence of death was justified—and brutally slaughters the wicked king on the spot. The phrase used here for Samuel's action is often translated along the lines of "hacked to pieces."

Although brutal, Samuel's work is a righteous act of obedience. This doesn't indicate a widespread command for all God's people to do the same. Samuel acts to fulfill the Lord's very narrow, extremely specific command: to devote all of the Amalekites to destruction for their sins against God and His people. Shortly after the exodus, during the time of Moses, the Amalekites attacked the rear flank of the worn-out Israelites, cutting off and killing the stragglers (Exodus 17:8–16). The Lord condemned them then for demonstrating their lack of fear in Him after He had just shown His power in Egypt. The Lord had said that when the time was right, Israel would blot out the memory of the Amalekites (Deuteronomy 25:17–19).