‏ Matthew 7:16-18

Verse 16

Ye shall know them by their fruits - Fruits, in the Scripture and Jewish phraseology, are taken for works of any kind. "A man's works," says one, "are the tongue of his heart, and tell honestly whether he is inwardly corrupt or pure." By these works you may distinguish (επιγνωσεσθε) these ravenous wolves from true pastors. The judgment formed of a man by his general conduct is a safe one: if the judgment be not favorable to the person, that is his fault, as you have your opinion of him from his works, i.e. the confession of his own heart.
Verse 17

So every good tree - As the thorn can only produce thorns, not grapes; and the thistle, not figs, but prickles; so an unregenerate heart will produce fruits of degeneracy. As we perfectly know that a good tree will not produce bad fruit, and the bad tree will not, cannot produce good fruit, so we know that the profession of godliness, while the life is ungodly, is imposture, hypocrisy, and deceit. A man cannot be a saint and a sinner at the same time. Let us remember, that as the good tree means a good heart, and the good fruit, a holy life, and that every heart is naturally vicious; so there is none but God who can pluck up the vicious tree, create a good heart, plant, cultivate, water, and make it continually fruitful in righteousness and true holiness.
Verse 18

A good tree cannot bring forth evil fruit - Love to God and man is the root of the good tree; and from this principle all its fruit is found. To teach, as some have done, that a state of salvation may be consistent with the greatest crimes, (such as murder and adultery in David), or that the righteous necessarily sin in all their best works, is really to make the good tree bring forth bad fruit, and to give the lie to the Author of eternal truth.
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