We are of God: he that knoweth God heareth us; he that is not of God heareth not us. Hereby know we the spirit of truth, and the spirit of error. We are of God - We, apostles, have the Spirit of God, and speak and teach by that Spirit. He that knoweth God - who has a truly spiritual discernment, heareth us - acknowledges that our doctrine is from God; that it is spiritual, and leads from earth to heaven.
Hereby know we the Spirit of truth - The doctrine and teacher most prized and followed by worldly men, and by the gay, giddy, and garish multitude, are not from God; they savor of the flesh, lay on no restraints, prescribe no cross-bearing, and leave every one in full possession of his heart's lusts and easily besetting sins. And by this, false doctrine and false teachers are easily discerned.