Job 8:12

Whilst it is yet in his greenness - We do not know enough of the natural history of this plant to be able to discern the strength of this allusion; but we learn from it that, although this plant be very succulent, and grow to a great size, yet it is short-lived, and speedily withers; and this we may suppose to be in the dry season, or on the retreat of the waters of the Nile. However, Soon Ripe, soon Rotten, is a maxim in horticulture.

Whilst it is yet in his greenness - That is, while it seems to be in its vigor.

And is not cut down - Even when it is not cut down. If suffered to stand by itself, and if undisturbed, it will wither away. The application of this is obvious and beautiful. Such plants have no self sustaining power. They are dependent on moisture for their support. If that is withheld, they droop and die. So with the prosperous sinner and the hypocrite. His piety, compared with that which is genuine, is like the spongy texture of the paper-reed compared with the solid oak. He is sustained in his professed religion by outward prosperity, as the rush is nourished by moisture; and the moment his prosperity is withdrawn, his religion droops and dies like the flag without water.

8:12 Greenness - Whereby it promises long continuance. Tho' no man cut it down, it withers of itself, sooner than other herbs.