Albert Barnes Commentary Matthew 7:16

"By their fruits ye shall know them. Do [men] gather grapes of thorns, or figs of thistles?" — Matthew 7:16 (ASV)

You shall know them by their fruits. He gives the proper test of their character. People do not judge a tree by its leaves, bark, or flowers, but by the fruit it bears. The flowers may be handsome and fragrant; the foliage thick and green; but these are merely ornamental. It is the fruit that is of primary service to people; and they form their opinion of the nature and value of the tree by its fruit. So it is with religious professions. The profession may appear good; but the conduct—the fruit in the eye of the world—determines the nature of the principles.