John Gills Exposition of the Bible Commentary - Proverbs 28:26
He that trusteth in his own heart is a fool ,.... Since the thoughts and imaginations of the thoughts of the heart are only evil, and that continually; they are vain and vague, sinful and corrupt; the affections are inordinate, the conscience defiled, the understanding darkened, and the will perverse; there is no good thing in it, nor any that comes out of it, but all the reverse; it is deceitful and desperately wicked: he must be a fool, and not know the plague of his heart, that trusts in... read more
Matthew Henry's Complete Commentary - Proverbs 28:26
Here is, 1. The character of a fool: He trusts to his own heart, to his own wisdom and counsels, his own strength and sufficiency, his own merit and righteousness, and the good opinion he has of himself; he that does so is a fool, for he trusts to that, not only which is deceitful above all things (Jer. 17:9), but which has often deceived him. This implies that it is the character of a wise man (as before, Prov. 28:25) to put his trust in the Lord, and in his power and promise, and to follow... read more