What does 1 Samuel 15:3 mean?
The Lord is commanding Saul, king of Israel, to attack the Amalekites and utterly wipe them out. In fact, God tells Saul to leave nothing left alive. This command is absolute and includes men, women, children, animals, and livestock. The Lord is clear that every living thing should be killed. The phrase "devote them to destruction" is from the Hebrew root word ḥāram (Joshua 6:17). This refers to an absolute, inviolable decision. This work of Israel is out of obedience and as a kind of offering to the Lord. In other words, Israel is to be the instrument of God's judgment on Amalek. They are not to profit from this war.This command does not describe the impulsive raging of an out-of-control God. This is the Lord commanding His people to fulfill His own four-hundred-year-old declaration of judgment on Amalek. They had attacked Israel as God's people were escaping from slavery in Egypt (Deuteronomy 25:17–19). That assault is described in Exodus 17:8–16. Moses stood during the battle, hands raised with the "staff of God," while Joshua and the Israelite army fought. When Moses lowered his hands, the enemy was successful. So, as Moses fatigued, he sat down while Aaron and Hur held his hands up. Joshua and the Israelites experienced victory. And God commanded Moses, "Write this as a memorial in a book and recite it in the ears of Joshua, that I will utterly blot out the memory of Amalek from under heaven" (Exodus 17:14). At the celebration that followed, Moses declared that the Lord would have war with Amalek from generation to generation (Exodus 17:16). Deuteronomy 25:18 says that Amalek "did not fear God," and they would be judged because of it.
God's command to kill every person and animal of a people sounds devastatingly harsh to modern ears. It's essential to remember, that one of God's purposes for His people was to bring judgment on tribes that had been practicing depraved evil in His sight generation after generation (Deuteronomy 20:17–19). Part of Israel's purpose in the world was to be used by God to accomplish this purpose.