The mountains shall bring peace to the people, and the little hills, by righteousness.

Let the mountains receive peace for the people: and the hills justice.

The mountains bear peace to the people, And the heights by righteousness.

Let the mountains bear peace to the people, and the hills, through righteousness.

The mountains shall bring peace to the people - The idea in this verse is that the land would be full of peace and the fruits of peace. All parts of it would be covered with the evidences that it was a land of quietness and security, where people could pursue their callings in safety, and enjoy the fruit of their labors. On the mountains and on all the little hills in the land there would be abundant harvests, the result of peace (so strongly in contrast with the desolations of war) - all showing the advantages of a peaceful reign. It is to be remembered that Judea is a country abounding in hills and mountains, and that a great part of its former fertility resulted from terracing the hills, and cultivating them as far as possible toward the summit. The idea here is, that one who should look upon the land - who could take in at a glance the whole country - would see those mountains and hills cultivated in the most careful manner, and everywhere bringing forth the productions of peace. Compare Psalm 65:11-13. See also the notes at Psalm 85:11-12.
And the little hills, by righteousness - That is, By the prevalence of righteousness, or under a reign of righteousness, the little hills would furnish illustrations of the influence of a reign of peace. Everywhere there would be the effects of a reign of peace. The whole land would be cultivated, and there would be abundance. Peace always produces these blessings; war always spreads desolation.

The mountains shall bring peace - Perhaps mountains and hills are here taken in their figurative sense, to signify princes and petty governors; and it is a prediction that all governors of provinces and magistrates should administer equal justice in their several departments and jurisdictions; so that universal peace should be preserved, and the people be every where prosperous; for שלום shalom signifies both peace and prosperity, for without the former the latter never existed.
But what is the meaning of "the little hills by righteousness?" Why, it has no meaning: and it has none, because it is a false division of the verse. The word בצדקה bitsedakah, in righteousness, at the end of Psalm 72:3, should begin Psalm 72:4, and then the sense will be plain. Psalm 72:3 : "The mountains and the hills shall bring prosperity to the people." Psalm 72:4 : "In righteousness he shall judge the poor of the people: he shall save the children of the needy, and shall break in pieces the oppressor."
The effects, mentioned in the fourth verse, show that King Solomon should act according to the law of his God; and that all officers, magistrates, and governors, should minister equal rights through every part of the land. The Septuagint has the true division: Αναλαβετω τα ορη ειρηνην τῳ λαῳ σου, και οἱ βουνοι· Εν δικαιοσυνῃ κρινει τους πτωχους του λαου, κ. τ. λ. "The mountains shall bring peace to thy people, and the hills: In righteousness shall he judge the poor of thy people," etc.

The (d) mountains shall bring peace to the people, and the little hills, by righteousness.
(d) When justice reigns, even the places most barren will be enriched with your blessings.

The mountains shall bring peace to the people,.... The people of God, as before. Kimchi and Ben Melech interpret this of the nations, and kings of the nations, comparable to mountains and hills, as in Micah 6:1; that should make peace with Israel in the days of Solomon, and in the days of the King Messiah. Jarchi, of the abundance of fruit the mountains and hills should bring forth; so that there would be no contention among men about gathering it; but everyone would invite his neighbour to partake thereof, according to Zac 3:10, and so the Midrash (p). The Targum explains it of the inhabitants of the mountains; and may be applied to the churches of Christ, comparable to the mountains for their firmness and stability, Isaiah 2:2; and to the abundance of peace, holiness, and righteousness, that should be found in them in the times of Christ; or to the ministers of the Gospel, whose feet are beautiful, upon the mountains publishing peace and salvation by Christ, Isaiah 52:7;
and the little hills by righteousness: that is, shall bring peace, by or with righteousness, the righteousness of Christ; the effect of which is spiritual peace and joy, Romans 5:1.
(p) In Yalkut Simeoni, ut supra. (par. 2. fol. 112. 2.)

As mountains and hills are not usually productive, they are here selected to show the abundance of peace, being represented as
bringing--or, literally, "bearing" it as a produce.
by righteousness--that is, by means of his eminently just and good methods of ruling.

The mountains - Which are so dangerous to passengers, in regard of robbers and wild beasts. Hereby it is implied, that other places should do so too, and that it should be common and universal.