So, every healthy tree bears good fruit, but the diseased tree bears bad fruit.
We have here a caution against false prophets, to take heed that we be not deceived and imposed upon by them. Prophets are properly such as foretel things to come; there are some mentioned in the Old Testament, who pretended to that without warrant, and the event disproved their pretensions, as Zedekiah, Kg1 22:11, and another Zedekiah, Jer 29:21.
Commenting on Matthew 7:15-20
Every tree that bringeth not forth good fruit,.... Every preacher and teacher that does not bring the Gospel of Christ with him, and plainly and faithfully preach it to the people, sooner or later, is hewn down: however he may have appeared as a tall lofty cedar, and have carried it with a high hand against Christ and his Gospel, spoke "great swelling words of...
Verse 17. A corrupt tree. The word corrupt here does not signify, as our translation would seem to indicate, that the tree had been good, but had become vitiated; but that it was a tree of a useless character, of a nature that produces nothing beneficial. (f) "good tree"