I John 4:6 “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.”
John points out that there are two opposing spirits; “the spirit of truth” and “the spirit of error”. In this context the word “spirit” refers to the force of human zeal and commitment to keep and promote a body of assertions. Some assertions are true, and some are false. The “spirit of truth” asserts the true “doctrine of Christ” (II John 1:9); but, “the spirit of error” denies the true “doctrine of Christ” and asserts the “doctrines of men” (Colossians 2:22). It is referred to as “the spirit of truth” because they who “are of God” strive with all their God-given strength to cling to and maintain the true “doctrine of Christ”. But, they who are not “of God” strive with all their natural ability to drive away and destroy the “truth” of Jesus Christ. Thus, we clearly “know” the difference between those who cling to “the spirit of truth” and those who fight against the “truth” with “the spirit of error”. The conflict between “the spirit of truth” and “the spirit of error” is often called Spiritual Warfare. The Biblical way to fight this “Spiritual Warfare” is to learn the Word of God and profess it with all zeal and reason with those who are reasonable. But, history reveals that this Warfare has often resulted in brutal wars between nations and peoples. Let us strive with all diligence to reason our way this Warfare and pray that God will protect us from physical Warfare.