Whosoever shall confess He repeats the truth, that we are united to God by Christ, and that we cannot be connected with Christ except, God abides in us. Faith and confession are used indiscriminately in the same sense; for though hypocrites may wisely boast of faith, yet the apostle here acknowledges none of those who ordinarily confess, but such as truly and from the heart believe. Besides, when he says that Jesus is the Son of God, he briefly includes the sum and substance of faith; for there is nothing necessary for salvation which faith finds not in Christ After having said in general, that men are so united to Christ by faith, that Christ unites them to God, he subjoined what they themselves had seen so that he accommodated a general truth to those to whom he was writing. Then follows the exhortation, to love one another as they were loved by God. Therefore the order and connection of his discourse is this, -- Faith in Christ, makes God to dwell in men, and we are partakers of this grace; but as God is love, no one dwells in him except he loves his brethren. Then love ought to reign in us, since God unites himself to us.

Whosoever shall confess that Jesus is the Son of God - In the true sense, and from the heart. This will always prove that a man is a Christian. But the passage cannot mean that if he merely says so in words, or if he does it insincerely, or without any proper sense of the truth, it will prove that he is a Christian. On the meaning of the sentiment here expressed, see the notes at 1-John 4:2. Compare the notes at Romans 10:10.

Whosoever shall confess - Much stress is laid on this confession, because the false teachers denied the reality of the incarnation; but this confession implied also such a belief in Christ as put them in possession of his pardoning mercy and indwelling Spirit.

Whosoever shall (h) confess that Jesus is the Son of God, God dwelleth in him, and he in God.
(h) With such a confession as comes from true faith, and is accompanied with love, so that there is an agreement of all things.

Whosoever shall confess that Jesus is the Son of God,.... The only begotten of the Father; that he is not a mere man, as the Jews, and Ebion and Cerinthus said, but a divine person, equal with the Father; which contains all that relates to the dignity of his person, and his fitness for his office as a Saviour, and which was the test of faith in those times, and the grand article of belief: not that a bare assent to this had what followed annexed to it; for the devils believed and owned that Jesus was the Son of God; and so might, and did, unregenerate persons, as the centurion at the cross of Christ, who know nothing what communion with God is; but this confession is such as is attended with a believing in Christ from the heart unto righteousness, life, and salvation, and a cheerful obedience to his ordinances and commands, from a principle of love to him, and faith in him, things not to be found in devils and carnal men; see Romans 10:9.
God dwelleth in him, and he in God; See Gill on 1-John 4:13; this should encourage to an open and hearty confession of Christ as the Son of God, and Saviour of sinners, and to a public profession of his name, and faith in him, and an holding it fast without wavering.

shall confess--once for all: so the Greek aorist means.
that Jesus is the Son of God--and therefore "the Saviour of the world" (1-John 4:14).

Whosoever shall, from a principle of loving faith, openly confess in the face of all opposition and danger, that Jesus is the Son of God, God abideth in him.