Spirit Indwelling
Knowing the Spirit of Truth
Two new themes appear in this verse. The first theme is the epistle’s first reference to God, or Christ, abiding in each obedient believer. Those who obey His commands (cf. 2:3; 3:23; 5:2–3) live (menei, “abide”) in Him, and He in them. That the abiding life involves this mutuality is made plain in the Parable of the Vine and the Branches (John 15:4–5, 7).
The second new idea is the epistle’s first of six explicit references to the Holy Spirit (cf. 1 John 4:2, 6, 13; 5:6, 8; cf. “the Holy One” in 2:20). The way a believer can verify that God lives (menei, “abides”) in him is by the operation of God’s Spirit in his life. John then showed that God’s Spirit is the Spirit of both faith (4:1–6) and love (4:7–16)—the two aspects of the two-part “command” given in 3:23.
Recognize who is speaking to you.
Victory through the Spirit
Reliance on God is the secret of all victory whether over heresy or any other snare. The indwelling One—the Holy Spirit who indwells every believer (3:24; 4:13; Rom. 8:9) and is thus “the One who is in you”—is mightier than the one who is in the world, namely, Satan (cf. 1 John 5:19). He is called “the prince of this world” (John 12:31); “the god of this Age” (2 Cor. 4:4); and “the ruler of the kingdom of the air” (Eph. 2:2).
Each one who can be described as “from God” (i.e., actuated and influenced by God) and thus knows God listens to the apostolic voice. In the history of the church, apostolic doctrine has always been the means by which the Holy Spirit of truth and the spirit of falsehood can be effectively distinguished. True Christianity is apostolic Christianity.