2 Samuel 18:8

the forest devoured more people: The land in the forest (its rough ground and thick growth) removed the numerical advantage of Absalom’s army.

the wood devoured more people than the sword--The thick forest of oaks and terebinths, by obstructing the flight, greatly aided the victors in the pursuit.

Which way David raised an army here, and what reinforcements were sent him, we are not told; many, it is likely, from all the coasts of Israel, at least from the neighbouring tribes, came in to his assistance, so that, by degrees, he was able to make head against Absalom, as Ahithophel foresaw. Now here we have,
I. His army numbered and marshalled, Sa2 18:1, Sa2 18:2. He had, no doubt, committed his cause to God by prayer, for that was his relief in all his afflictions; and then he took an account of his forces. Josephus says they were, in all, but about 4000. These he divided into regiments and companies, to each of which he appointed proper officers, and then disposed them, as is usual, into the right wing, the left wing, and the centre, two of which he committed to his two old experienced generals, Joab and Abishai, and the third to his new friend Ittai. Good order and good conduct may sometimes be as serviceable in an army as great numbers. Wisdom teaches us to make the best of the strength we have, and let it reach to the utmost.
II. Himself over-persuaded not to go in person to the battle. He was Absalom's false friend that persuaded him to go, and served his pride more than his prudence; David's true friends would not let him go, remembering what they had been told of Ahithophel's design to smite the king only. David showed his affection to them by being willing to venture with them (Sa2 18:2), and they showed theirs to him by opposing it. We must never reckon it an affront to be gain-said for our good, and by those that therein consult our interest. 1. They would by no means have him to expose himself, for (say they) thou art worth 10,000 of us. Thus ought princes to be valued by their subjects, who, for their safety, must be willing to expose themselves. 2. They would not so far gratify the enemy, who would rejoice more in his fall than in the defeat of the whole army. 3. He might be more serviceable to them by tarrying in the city, with a reserve of his forces there, whence he might send them recruits. That may be a post of real service which yet is not a post of danger. The king acquiesced in their reasons, and changed his purpose (Sa2 18:4): What seemeth to you best I will do. It is no piece of wisdom to be stiff in our resolutions, but to be willing to hear reason, even from our inferiors, and to be overruled by their advice when it appears to be for our own good. Whether the people's prudence had an eye to it or no, God's providence wisely ordered it, that David should not be in the field of battle; for then his tenderness would certainly have interposed to save the life of Absalom, whom God had determined to destroy.
III. The charge he gave concerning Absalom, Sa2 18:5. When the army was drawn out, rank and file, Josephus says, he encouraged them, and prayed for them, but withal bade them all take heed of doing Absalom any hurt. How does he render good for evil! Absalom would have David only smitten. David would have Absalom only spared. What foils are these to each other! Never was unnatural hatred to a father more strong than in Absalom; nor was ever natural affection to a child more strong than in David. Each did his utmost, and showed what man is capable of doing, how bad it is possible for a child to be to the best of fathers and how good it is possible for a father to be to the worst of children; as if it were designed to be a resemblance of man's wickedness towards God and God's mercy towards man, of which it is hard to say which is more amazing. "Deal gently," says David, "by all means, with the young man, even with Absalom, for my sake; he is a young man, rash and heady, and his age must excuse him; he is mine, whom I love; if you love me, be not severe with him." This charge supposes David's strong expectation of success. Having a good cause and a good God, he doubts not but Absalom would lie at their mercy, and therefore bids them deal gently with him, spare his life and reserve him for his judgment.
Bishop Hall thus descants on this: "What means this ill-placed love? This unjust mercy? Deal gently with a traitor? Of all traitors, with a son? Of all sons, with an Absalom? That graceless darling of so good a father? And all this, for thy sake, whose crown, whose blood, he hunts after? For whose sake must he be pursued, if forborne for thine? Must the cause of the quarrel be the motive of mercy? Even in the holiest parents, nature may be guilty of an injurious tenderness, of a bloody indulgence. But was not this done in type of that immeasurable mercy of the true King and Redeemer of Israel, who prayed for his persecutors, for his murderers, Father, forgive them? Deal gently with them for my sake." When God sends and affliction to correct his children, it is with this charge, "Deal gently with them for my sake;" for he knows our frame.
IV. A complete victory gained over Absalom's forces. The battle was fought in the wood of Ephraim (Sa2 18:6), so called from some memorable action of the Ephraimites there, though it lay in the tribe of Gad. David thought fit to meet the enemy with his forces at some distance, before they came up to Mahanaim, lest he should bring that city into trouble which had so kindly sheltered him. The cause shall be decided by a pitched battle. Josephus represents the fight as very obstinate, but the rebels were at length totally routed and 20,000 of them slain, Sa2 18:7. Now they smarted justly for their treason against their lawful prince, their uneasiness under so good a government, and their base ingratitude to so good a governor; and they found what it was to take up arms for a usurper, who with his kisses and caresses had wheedled them into their own ruin. Now where are the rewards, the preferments, the golden days, they promised themselves from him? Now they see what it is to take counsel against the Lord and his anointed, and to think of breaking his bands asunder. And that they might see that God fought against them, 1. They are conquered by a few, an army, in all probability, much inferior to theirs in number. 2. By that flight with which they hoped to save themselves they destroyed themselves. The wood, which they sought to for shelter, devoured more than the sword, that they might see how, when they thought themselves safe from David's men, and said, Surely the bitterness of death is past, yet the justice of God pursued them and suffered them not to live. What refuge can rebels find from divine vengeance? The pits and bogs, the stumps and thickets, and, as the Chaldee paraphrase understands it, the wild beasts of the wood, were probably the death of multitudes of the dispersed distracted Israelites, besides the 20,000 that were slain with the sword. God herein fought for David, and yet fought against him; for all these that were slain were his own subjects, and the common interest of his kingdom was weakened by the slaughter. The Romans allowed no triumph for a victory in a civil war.

The wood devoured more people - It is generally supposed that, when the army was broken, they betook themselves to the wood, fell into pits, swamps, etc., and, being entangled, were hewn down by David's men; but the Chaldee, Syriac, and Arabic, state that they were devoured by wild beasts in the wood.

For the battle was there scattered over the face of all the country,.... Or the warriors were scattered, as the Targum; Absalom's soldiers, their ranks were broken, and they were thrown into the utmost confusion, and ran about here and there all over the field or plain in which the battle was fought, and into the neighbouring wood:

and the wood devoured more people that day than the sword devoured; there were more slain in it the in the field of battle, what by one thing or another; as by falling into pits and on stumps of trees, and being entangled in the bushes, and could make but little haste, and so were overtaken by David's men, and slain; insomuch that, as Josephus (h) observes, there were more slain fleeing than fighting, and perhaps some might perish by wild beasts; so the Targum,"and the beasts of the wood slew more of the people than were slain by the sword;''and so the Syriac and Arabic versions render the words to the same purpose.

(h) Ut supra. (Antiqu. l. 7. c. 10. sect. 2.)

The battle was there scattered, i. e. the warriors being beaten in the fight, fled, and were dispersed; the abstract being put for the concrete, as poverty is put for poor men, , and deceit for the deceiver, and dreams for dreamers, 13:6.

The wood devoured more people, i.e. more people died in the wood, either through hunger, and thirst, and weariness; or by the wild beasts, whereof great numbers were there, which, though they were driven away by noise and clamour from the place of the main battle, yet might easily meet with them when they fled several ways, which also might be directed and sent to them by God’ s providence and just judgment to punish them for their rebellion; or by falling into ditches and pits, which were in that place, , and probably were covered with grass or wood, so as they could not see them till they fell into them; or by being hanged in trees, as Absalom was, ; and especially by David’ s men, who pursued them, and killed them in the wood: and the wood is rightly said to have devoured them, because it gave the occasion to their destruction, inasmuch as the trees, and ditches, and pits, entangled them, and stopped their flight, and made them an easy prey to David’ s men, who followed them, and slew them in the pursuit, being therein directed and assisted by the people of that country, who, after the manner, fell in with the victorious side.

Than the sword devoured, to wit, in the main battle; the sword being put for the battle, by a common metonymy.

The conflict extended over the surface of the whole land, i.e., the whole of that region (the Chethib נפצות is not the plural נפצות, which would be quite unsuitable, but is most probably a noun, נפצוּת ,nuon a, signifying bursting asunder, or wild flight; the Keri נפצת is a Niphal participle, fem. gen.); "and the wood devoured more of the people than the sword ate on the same day." The woody region was most likely full of ravines, precipices, and marches, into which the flying foe was pursued, and where so many perished.