Mountains, and all hills - As being among the loftiest objects of earth, raising their heads highest toward the heavens.
Fruitful trees, and all cedars - Fruitful trees, not as distinguished from those which are barren, but as distinguished from forest-trees, those whose nature is that they do not bear fruit. Of the latter, the cedar was the most prominent, and, therefore, is made the representative of the whole.

Mountains, and all hills - Whether primitive, secondary, or alluvial; of ancient or recent formation, with all their contents, quarries, mines, and minerals. But what a profusion of wisdom and skill is lavished on these! To instance only in the different metals, earths, and minerals; especially the precious stones.
Fruitful trees - עץ פרי ets peri, fruit trees of all kinds.
And all cedars - Every kind of forest tree. The formation of the fruits, their infinitely varied hues and savours, proclaim the unsearchable wisdom and goodness of God: not less so, the growth, structure, and various qualities and uses of the forest trees.

Mountains, and all hills,.... Which are originally formed by the Lord, and set fast by his power and strength; these are the highest parts of the earth, and are very ornamental and useful; they include all in them and upon them, the trees and herbage that grow upon them, gold, silver, brass, and iron in them; all very beneficial to mankind, and afford matter of praise to God for them; see Isaiah 55:12;
fruitful trees, and all cedars; trees bearing fruit are the fig trees, pomegranates, vines, and olives, with which the land of Canaan abounded; and such as bear lemons, oranges, plums, pears, apples, cherries, &c. which produce fruit for the use, pleasure, and delight of man, and so a means of praising God: and "cedars", the trees of the Lord which he hath planted; though they bear no fruit, yet very useful in building, and were of great service in the temple at Jerusalem; and which are put for all others of like usefulness, and minister just occasion of praise; see Psalm 96:12.

fruitful trees--or, "trees of fruit," as opposed to forest trees. Wild and domestic, large and small animals are comprehended.