Charles Ellicott Commentary Psalms 148:9

"Mountains and all hills; Fruitful trees and all cedars;" — Psalms 148:9 (ASV)

Mountains, and all hills.—The invocation now alights on the crests of the highest mountains, and passes downward to the lower hills where vegetable life begins.

Fruitful trees.— Rather, fruit trees; the fruit-bearing tree is representative of one division of the vegetable world, planted and cultivated by humans, and the cedars are representative of the other division, which are (Psalms 104:16) of God’s own plantation.