31:5 a thousand. Since the average number of adult males per tribe was about 50,000 (compare Numbers 26:51), this means that only about one in fifty participated in the actual fighting.

31:6 holy instruments. This was considered a holy war, ordered by God Himself (Numbers 31:1) to avenge His honor and that of His people, so it was led by the priest Phinehas who had slain the leaders in the offensive action (Numbers 25:7-8), causing God’s judicial plague on His people for their adulterous idolatries to be stayed.

31:7 Midianites. The Midianites were a group of nomadic tribes descended from Abraham through his later wife, Keturah (Genesis 25:1-4). This particular tribe of Midianites were apparently closely allied with the Moabites, and seem to have participated at least equally with the Moabites in the seduction of Israel into fornication and idolatry (note Numbers 25:6,16-18).

31:8 Balaam. The sad end of Balaam indicates that no one, regardless of his great spiritual gifts, is immune from falling if he forsakes God’s revealed will for his own temporal advantage. Balaam knew God and had the gift of prophecy. Even in his self-willed compromise, he was still given marvelous revelations, uttering amazing prophecies that would be brought to fulfillment by God many centuries later. Yet, frustrated in his desire to advance his own position and wealth, and to promote his own people against God’s chosen people, he then counseled the Moabites to tempt the Israelites into adultery and idolatry with the Moabite women (Numbers 25:1-5; 31:16). He apparently sought to destroy by seduction those whom he could not destroy by might. Hence his sad end.

31:15 saved all the women. The Midianite women had evidently been willing participants in the seduction of Israel, and God had commanded that they, as well as the Midianite men, be put to death (Numbers 25:17,18). No less than 24,000 Israelites had already been slain by God for this grievous sin (Numbers 25:9). Half that number were now sent to destroy the Midianite men and women; evidently all of these had been either actively participating or passively approving in the attempt to destroy Israel. Their sin was more unconscionable in God’s sight than the sins of the Amorites and Canaanites, who had already been designated for destruction by God because they–being descended from Abraham and having Moses’ own father-in-law as one of their priests (Exodus 3:1)–were a kindred nation to the children of Israel.

31:18 keep alive for yourselves. The only ones to be spared execution were the young virgin women of Midian, who could be brought back to their ancestral faith by living with an Israelite family and eventually marrying an Israelite man.

31:19 whosoever hath touched. See Numbers 19:11. Anyone who had slain or had touched the slain, as well as any clothing or instruments that had touched the slain, had to be purified either by passing through the fire (Numbers 31:23) or by being washed by the water of purification made with the ashes of the red heifer (Numbers 19).

31:27 two parts. The spoils of the Midianite war were shared with those who had stayed “by the stuff” (compare I Samuel 30:24).

31:38 beeves. Plural of beef-cow.

31:49 lacketh not one man. This is a marvelous testimony of God’s providential protection of those who had willingly submitted to His will in carrying out a difficult and potentially dangerous task.