The mountains shall bring peace to the people, and the little hills, by righteousness.
The mountains shall bring peace to the people. "Shall bring" - literally, shall lift up, in the sense publish, or proclaim (Isaiah 40:9; Isaiah 52:7-8). "The mountains," as the prominent feature, represent the whole country; everywhere shall "peace" prevail (Joel 3:18). "Peace" is the characteristic, of Messiah's coming reign (Isaiah 2:4; Isaiah 9:5-6; Isaiah 11:9; Isaiah 65:25; Micah 4:3; Zechariah 9:10).
And the little hills, by righteousness - "and the little hills (shall bring peace obtained) by righteousness" (Psalms 85:11; Isaiah 45:8). Peace shall not be the product of a compromise with falsehood and wrong, but the result of righteousness (cf. Leviticus 26:3-6, the promise under the law). The name Solomon, meaning peaceful, is alluded to here (cf. 2 Kings 5:4).