YHWH Commands His Anointed To Slay The Amalekites As A Divine Judgment On Them (1 Samuel 15:1-3).
It is important to recognise in this passage that Saul is specifically instructed as ‘the anointed of YHWH' and is called on to act as His instrument of justice on the Amalekites. He is to ‘devote' the Amalekites and all their possessions to YHWH. This involved total annihilation and destruction of something which all recognised that YHWH had specifically made His own. It was all thus sacred to Him and non-negotiable. No exception was allowed. We can compare the story of Achan who also sought to keep for himself what had been devoted to YHWH and was visited with swift judgment (Joshua 7).
‘ And Samuel said to Saul, “YHWH sent me to anoint you to be king over his people, over Israel, now therefore listen to the voice of the words of YHWH,” '
Samuel now comes to Saul emphasising that he is the anointed of YHWH. That means that he is dedicated to doing YHWH's will. In view of that he is now to listen to the words of YHWH which will instruct him in what YHWH requires of him.
“ Thus says YHWH of hosts, I have marked what Amalek did to Israel, how he set himself against him in the way, when he came up out of Egypt. Now go and smite Amalek, and utterly destroy all that they have, and do not spare them, but slay both man and woman, infant and suckling, ox and sheep, camel and ass.”
What in fact YHWH requires of him is that he ‘devote' Amalek to YHWH. That will involve destroying the Amalekites and all connected with them. The idea of ‘devoting' a people in this way was that they were consecrated to God in judgment and must be offered to Him in their totality. Those who performed this work were seen to be acting as God's instruments of justice. For that reason they must take no benefit of it for themselves, for everything involved was ‘devoted' to and belonged to YHWH. We can compare how Jericho was also previously devoted to YHWH and how Achan was executed because he kept for himself certain ‘devoted things' (Joshua 6-7). Thus what Saul was being called on to do was a most sacred task, and as he knew perfectly well, not to carry it out to the letter would be sacrilege. This was not unique to Israel. Similar ideas were also found among surrounding countries such as Moab (it is referred to on the Moabite Stone), while evidence of it is also found at Mari.
The basis of it in this case was stated to be because the Amalekites were the first to attack the people of Israel as they came out of Egypt, when they were especially vulnerable in the wilderness (Exodus 17). The Amalekites had mercilessly swooped down on them, decimating their lines in order to obtain booty, and probably having also the aim of preventing them from passing through what they saw as Amalekite territory. These Amalekites were wandering tribespeople like the Bedouin today, and in those days they obtained much of their wealth by preying on others. They were a part of the alliance of tribes that caused such misery to the new nation of Israel in Judges 3:13; Judges 6:3-6, and they would think nothing of wiping out any whom they saw as intruding on their wide-ranging territory. They made an exception of small tribes like the Kenites whom they saw as also being genuine desert-dwellers. Some may well eventually have settled down to semi-nomadic living. But like the Canaanites/Amorites earlier, YHWH now saw them as having filled up their sins to the full (compare Genesis 15:16).
We should note that 1 Samuel 14:48 suggests that they had recently been despoiling the Israelites so that this was not just something out of the blue concerning things long past, but was a means of preventing further injury to the people of Israel. Total destruction was necessary because if such a people were not totally destroyed they would re-gather, associate with other tribespeople and subsequently take their revenge. The security of the people of Israel security thus demanded their annihilation. Nevertheless it was also to be seen as fulfilling God's curse on Amalek because of what they had previously done (Exodus 17:16; Numbers 24:20; Deuteronomy 25:17-19).
(We should note how long the Amalekites had had to repent of and change their ways. YHWH had not brought His curse into effect immediately. It was rather exacted as a result of further infringements.
The slaughter of all their cattle was seen as similar to offering up sacrifices to YHWH with the difference that it was done at once, without an altar and without any participation in the meat. All had been devoted to Him and was now being offered to Him. They would be slaughtered and then burned to ashes.
We should recognise that the whole point of The Ban (the devoting of people and things to YHWH) was that none would benefit from the slaughter. It was intended to be solemnly treated as an act of YHWH's judgment. We who live in less violent days, who do not sit in our houses and work in our fields wondering when the Amalekites will next sweep down on us and murder us all, cringe at the thought of this total destruction of a people, but we should remember that for people in those days there would have been no better news for them than that of their final deliverance from the threat of the depredations of the murderous Amalekites. To them it would have been like us locking up all the criminals at once.