Our apostle having spoken of the usefulness of faith in the former verse, that it overcometh the world, next discovers the object of this faith, which is this proposition, that Jesus is the Son of God.
Who is he that overcometh the world, but he that believeth that Jesus is the Son of God? That faith which overcomes the world, is faith in the divinity and sonship of Jesus Christ. We overcome the world by believing in him that overcame it, even Jesus Christ, who hath purchased, promised, and prepared a better world than what we do see, or can see, with our bodily eyes, and has made us heirs of eternal glory.
Observe next, The argument by which the apostle proves that Jesus is the Son of God, the true Messias and the Saviour of mankind, namely, because he came by water and blood; that is, say some, by the testimony given him when he was in the water, at his baptism, both by John the Baptist, and the voice from heaven; he came by his Spirit, say others, as by water, to sanctify those that believe in him; and by his blood to make a full atonement for them; and admirable symbol of both, which was the flowing of water and blood both out of Christ's side, when he hung upon the cross.
It is a sweet meditation that Christ comes by water as well as by blood, by way of sanctification as well as by way of justification; his death not only discharges from guilt, but cleanses also from pollution and filth; blessed be God there is a fountain opened in the side of our Saviour for sin, and for uncleanness to wash in, and to be purged from.
Sanctification is as great, and in some respects a greater privilege than justification; for justification frees us only from misery and punishment, but sanctification frees us from sin, which is worse than punishment.
Again, real perfections are above relative perfections; now justification by Christ's blood is only a relative perfection, it makes us stand in a new relation to the law, by which before we stood guilty and condemned: but sanctification by the Spirit of Christ, signified here, and set forth elsewhere frequently, by water, is a real moral perfection, it changes the heart and nature, and makes us like unto God, yea, like unto him in his highest perfection, which is that of holiness.
Come then, O blessed Redeemer, by water and blood into our souls, with thy renewing grace and sanctifying Spirit, to purge our consciences from dead works, and to deliver us not only from the danger, but from the dominion of our sins.
Some by the Spirit's bearing witness understand the testimony which the Holy Spirit gave to Christ here upon earth, as touching the truth of his doctrine, the reality of his miracles,and the certainty of his mission; others understand by it, the Spirit's testimony in the Holy Scriptures, and in the consciences of believers, that Jesus Christ, is a divine person, and came by water and blood, both to save us at once from the wrath of God, and the rage of our lusts.
Learn thence, That the Holy Spirit of God speaking in the Scriptures, and breathing in the consciences of believers, bears witness to their soul, that Jesus Christ came to save them by the water of sanctification, as well as with and by the blood of redemption; and that the Spirit thus witnessing is a Spirit of truth.