The second half of the psalm gives the dark contrast of the fruitless, rootless life (vv. 4-6). The Hebrew flashes the whole dread antithesis on the view at once by its first word, "Not so," a universal negative, which reverses every part of the preceding picture. "Wicked" is preferable to "ungodly," as the designation of the subjects. Whether we take the root idea of the word to be "restless," as most of the older and many modern commentators do, or "crooked" (Hupfeld), or "loose, flaccid" (Delitzsch), it is the opposite of "righteous," and therefore means one who lives not by the law of God, but by his own will. The psalmist has no need to describe him further nor to enumerate his deeds. The fundamental trait of his character is enough. Two classes only, then, are recognised here. If a man has not God's uttered will for his governor, he goes into the category of "wicked." That sounds harsh doctrine, and not corresponding to the innumerable gradations of character actually seen. But it does correspond to facts, if they are grasped in their roots of motive and principle. If God be not the supreme delight, and His law sovereign, some other object is men's delight and aim, and that departure from God taints a life, however fair it may be. It is a plain deduction from our relations to God that lives lived irrespective of Him are sinful, whatever be their complexion otherwise.
The remainder of the psalm has three thoughts--the real nullity of such lives, their consequent disappearance in "the judgment," and the ground of both the blessedness of the one type of character and the vanishing of the other in the diverse attitude of God to each. Nothing could more vividly suggest the essential nothingness of the "wicked" than the contrast of the leafy beauty of the fruit-laden tree and the chaff, rootless, fruitless, lifeless, light, and therefore the sport of every puff of wind that blows across the elevated and open threshing floor.
Such is indeed a true picture of every life not rooted in God and drawing fertility from Him. It is rootless; for what hold-fast is there but in Him? or where shall the heart twine its tendrils if not round God's stable throne? or what basis do fleeting objects supply for him who builds elsewhere than on the enduring Rock? It is fruitless; for what is fruit? There may be much activity and many results satisfying to part of man's nature and admired by others. One fruit there will be, in character elaborated. But if we ask what ought to be the products of a life, man and God being what they are in themselves and to each other, we shall not wonder if every result of godless energy is regarded by "those clear eyes and perfect judgment" of heaven as barrenness. In the light of these higher demands, achievements hymned by the world's acclamations seem infinitely small, and many a man, rich in the apparent results of a busy and prosperous life, will find to his dismayed astonishment that he has nothing to show but unfruitful works of darkness. Chaff is fruitless because lifeless.