Matthew 7:16-20

Matthew 7:16-20. Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth-good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth-evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.

You may judge men as well as trees that way; and you may judge doctrines that way. That which gives a license to sin cannot be true; but that which makes for holiness is true; for, somehow, truth of doctrine and holiness of life run together. We cannot expect holiness to grow out of falsehood, but we may expect all manner of evil to come out of false teaching.