Avenge the Lord of Midian - The war against the Midianites was no ordinary war. It was indeed less a war than the execution of a divine sentence against a most guilty people.

Doubtless there were many among the Midianites who were personally guiltless as regards Israel. But the rulers deliberately adopted the counsel of Balaam against Israel, and their behests had been but too readily obeyed by their subjects. The sin therefore was national, and the retribution could be no less so.

But the commission of the Israelites in the text must not be conceived as a general license to slay. They had no discretion to kill or to spare. They were bidden to exterminate without mercy, and brought back to their task Numbers 31:14 when they showed signs of flinching from it. They had no alternarive in this and similar matters except to fulfill the commands of God; an awful but doubtless salutary manifestation, as was afterward the slaughter of the Canaanites, of God's wrath against sin; and a type of the future extermination of sin and sinners from His kingdom.

Avenge the Lord of Midian - It was God's quarrel, not their own, that they were now to take up. These people were idolaters; idolatry is an offense against God; the civil power has no authority to meddle with what belongs to Him, without especial directions, certified in the most unequivocal way. Private revenge, extension of territory, love of plunder, were to have no place in this business; the Lord is to be avenged; and through Him the children of Israel, (Numbers 31:2), because their souls as well as their bodies had been well nigh ruined by their idolatry.

And Moses spake unto the people, saying,.... In obedience to the divine command; this must be supposed to be spoken to the heads or princes of the tribes:

arm some of yourselves unto the war: not the whole body of the militia, 600,000 men and upwards, only some of them, and these choice and select men; and, according to the Jewish writers, good men, who, detesting the sins of lewdness and idolatry, would more strictly and severely avenge themselves on the Midianites for drawing their brethren into those sins, whereby they fell; and so Jarchi calls them righteous men:

and let them go against the Midianites, and avenge the Lord of Midian: what the Lord calls the vengeance of the Israelites, Moses calls the vengeance of the Lord, because they were the Lord's people, and his cause and theirs the same: and because the sins they were drawn into by the Midianites were not only against themselves, and to their prejudice, but against the Lord and to the dishonour of his name.

To carry out this revenge, Moses had 1000 men of each tribe delivered (ימּסרוּ, see at Numbers 31:16) from the families (alaphim, see Numbers 1:16) of the tribes, and equipped for war; and these he sent to the army (into the war) along with Phinehas the son of Eleazar the high priest, who carried the holy vessels, viz., the alarm-trumpets, in his hand. Phinehas was attached to the army, not as the leader of the soldiers, but as the high priest with the holy trumpets (Numbers 10:9), because the war was a holy war of the congregation against the enemies of themselves and their God. Phinehas had so distinguished himself by the zeal which he had displayed against the idolaters (Numbers 25:7), that it was impossible to find any other man in all the priesthood to attach to the army, who would equal him in holy zeal, or be equally qualified to inspire the army with zeal for the holy conflict. "The holy vessels" cannot mean the ark of the covenant on account of the plural, which would be inapplicable to it; nor the Urim and Thummim, because Phinehas was not yet high priest, and the expression כּלי would also be unsuitable to these. The allusion can only be to the trumpets mentioned immediately afterwards, the ו before חצצרות being the ו explic., "and in fact." Phinehas took these in his hand, because the Lord had assigned them to His congregation, to bring them into remembrance before Him in time of war, and to ensure His aid (Numbers 10:9).

And Moses spake unto the people, saying, Arm some of yourselves unto the war, and let them go {a} against the Midianites, and avenge the LORD of Midian.

(a) As he had commanded in Nu 25:17, declaring also that the injury done against his people is done against him.

31:3 Avenge ye the Lord - For the affront which they offered to God, by their own idolatry and lewdness, and by seducing God's people into rebellion against him. God's great care was to avenge the Israelites, Nu 31:2, and Moses's chief desire was to avenge God rather than himself or the people.

3. Arm some of yourselves-This order was issued but a short time before the death of Moses. The announcement to him of that approaching event [Nu 31:2] seems to have accelerated, rather than retarded, his warlike preparations.

31:1-6 All who, without commission from God, dare to execute private revenge, and who, from ambition, covetousness, or resentment, wage war and desolate kingdoms, must one day answer for it. But if God, instead of sending an earthquake, a pestilence, or a famine, be pleased to authorize and command any people to avenge his cause, such a commission surely is just and right. The Israelites could show such a commission, though no persons now can do so. Their wars were begun and carried on expressly by Divine direction, and they were enabled to conquer by miracles. Unless it can be proved that the wicked Canaanites did not deserve their doom, objectors only prove their dislike to God, and their love to his enemies. Man makes light of the evil of sin, but God abhors it. This explains the terrible executions of the nations which had filled the measure of their sins.