Charles Spurgeon Commentary 1 John 4:5-6

"They are of the world: therefore speak they [as] of the world, and the world heareth them. We are of God: he that knoweth God heareth us; he who is not of God heareth us not. By this we know the spirit of truth, and the spirit of error." — 1 John 4:5-6 (ASV)

They are of the world; therefore they speak of the world, and the world hears them. We are of God: whoever knows God hears us; whoever is not of God does not hear us. By this we know the spirit of truth and the spirit of error.

If apostolic teaching is denied, those who deny it are not of God, for the Spirit of God was in the apostles, as he is also in all the Lord's true children.

By this test we may try many of the spirits of the present day: Whoever knows God hears us; whoever is not of God does not hear us. By this we know the spirit of truth and the spirit of error.

The apostle now gives us another infallible test by which we may try the spirits.