Charles H. Spurgeon on Psalms 72:3

The mountains shall bring peace to the people. Thence, aforetime, rushed the robber bands which infested the country; but now the forts there erected are the guardians of the land, and the watchmen publish far and near the tidings that no foe is to be seen. Where Jesus is there is peace, lasting, deep, eternal. Even those things which were once our dread, lose all terror when Jesus is owned as monarch of the heart: death itself, that dark mountain, loses all its gloom. Trials and afflictions, when the Lord is with us, bring us an increase rather than a diminution of peace. And the little hills, by righteousness. Seeing that the rule of the monarch was just, every little hill seemed clothed with peace. Injustice has made Palestine a desert; if the Turk and Bedouin were gone, the land would smile again; for even in the most literal sense, justice is the fertilizer of lands, and men are diligent to plough and raise harvests when they have the prospect of eating the fruit of their labours. In a spiritual sense, peace is given to the heart by the righteousness of Christ; and all the powers and passions of the soul are filled with a holy calm, when the way of salvation, by a divine righteousness, is revealed. Then do we go forth with joy, and are led forth with peace; the mountains and the hills break forth before us into singing.