A reminder of the background to the epistle might be a good run-in to chapter 5, for it will help to unravel some difficulties if we can remember the setting. John's readers had been targeted by Gnostic philosophers. Among other things, they suggested that "The Christ" was some kind of divine emanation that came upon Jesus at His baptism and left Him before His death, possibly in Gethsemane. Keeping that in mind will enable us to understand vv.6-8 as referring to the water of His baptism and the blood of His cross; remembering that these men were antichrists and apostates will help us to grasp the character of the "sin unto death" (v.16).
Loving God (5.1-3)
Until now John had been explaining the evidence of the new birth in terms of a person's behaviour: doing righteousness; not habitually sinning; loving (2.29; 3.9; 4.7). Now he focuses on belief, for belief and behaviour must go in tandem (v.5). Those who are "born of God" are people who believe, and never stop believing, that "Jesus is the Christ"; they believe that "Jesus is the Son of God" (v.5). Genuine saving faith in Christ results in solid adherence to "the doctrine of Christ" (2 Jn v.9); commitment to that doctrine is a feature of the family of God. Such people will love their Father and consequently love "him also that is begotten of him", their fellow-believers. "Hiram was ever a lover of David" and hence his practical interest and support for Solomon who was "begotten of him" (1 Kings 5.1). It is incongruous to love a father and to neglect his son, so really John is continuing the argument he commenced at the end of ch.4; claiming to love invisible Deity while at the same time loathing His visible offspring is totally inconsistent.
How can we assess if our love for "the children of God" is appropriate and valid? Of necessity it will go hand-in-glove with a love for God that is expressed in obedience (v.2). Love for God's people will never condone their sin or assist them to violate God's commandments. For example, to sanction an unequal yoke, or to be happy with an unbaptised believer participating in the Lord's Supper, or to socialise with someone under assembly discipline are expressions of sentimentality rather than love. Love for God's children is interwoven with love for God and keeping His commandments. Love "rejoiceth with the truth" (1 Cor 13.6, RV).
"If ye love me, keep my commandments" (Jn 14.15). John had heard it in the upper room and it was etched indelibly on his mind. Now the Spirit inspires him to express these same sentiments. Following the teaching of vv.1-2, "the love of God" here must mean our love for God. How is it expressed? Once more the stress is on works and not words, walk and not talk. In 2.3, keeping His commandments proves that "we know him"; here, keeping His commandments proves that we love Him. The word "commandments" sounds very demanding, but John assures us that "his commandments are not grievous". The word "grievous" carries the thought of something burdensome. The Lord used it when describing the wearisome, exacting rules of the Pharisees; "heavy burdens and grievous to be borne" (Mt 23.4). He invited those who were "heavy laden" by those petty regulations to come to Him for rest, and to take His yoke, "For my yoke is easy, and my burden is light" (Mt 11.28-30). Assistance to implement divine commands is always available for those "who walk not after the flesh, but after the Spirit" (Rom 8.4). They can say with David, "in keeping of them there is great reward" (Ps 19.11); immense pleasure is derived from obedience.
Overcoming the World (5.4-5)
Another feature of those who have been "born of God" is that they overcome the world. Young men overcame the wicked one (2.14); Spirit-taught believers overcame the antichrists (4.1-3); people who have been genuinely born again overcome the world. What is meant by "the world" was explained (2.15), but the tense of the verb "overcometh" indicates that there is no end to the war with the world; there is constant conflict. The world has never kept God's commandments (v.2) but the person who believes "that Jesus is the Son of God" submits to these commands and thus places himself at variance with the world. Morally, ethically, and in life-style you are different, and "they think it strange that ye run not with them to the same excess of riot", and so they will "(speak) evil of you" (1 Pet 4.4). This hostile reaction could prove to be an inducement to compromise and to conform, but true faith will give no ground, and will refuse to capitulate to the enchantments of the world; "this is the victory that overcometh the world, even our faith". It is sadly possible that someone who is perceived to be a "worldly Christian" is not that at all, but simply a worldly person devoid of saving faith. The Son of God declared, "be of good cheer; I have overcome the world" (Jn 16.33). Genuine faith in Him allows us to share His victory.
Water and Blood (5.6-9)
Once again, the object of our faith is said to be Jesus, the Son of God. That brings John to refute antichrist assertions that it was only the man Jesus who had died and that the divine emanation that had come upon Him at His baptism had departed before His death. No, says John, "This is he that came by water and blood…not by water only, but by water and blood". John stresses that it was the Son of God who was baptised in water at the commencement of His public ministry and it was the same Son of God who shed His precious blood at the end; these events were the two extremities of His public ministry. At His baptism the Father's voice witnessed to His Sonship. At the cross His absolute control of circumstances bore witness to His Sonship and deity; no mere man could have claimed what proved to be true, "No man taketh (my life) from me" (Jn 10.18). Thus the water and the blood give witness to His Sonship.
Then a third witness is introduced (vv.7-8), "the Spirit that beareth witness". He is a reliable contributor to the debate, for "the Spirit is truth". By inspiring Scripture relating to the Son, and empowering preaching about the Son, the Holy Spirit added weight to the testimony of the events at His baptism and death, and so "these three agree in one". The true identity of Jesus as the Son of God is established at the mouth of three witnesses. We were not present to hear the Father's voice at His baptism, nor were we present when His blood was shed, but we have the abiding witness of the Holy Spirit, which is relevant to the teaching of v.10.
Taken together, the three-fold witness is described as "the witness of God which he hath testified of his Son" (v.9). In human relations we have to take what is said at face value, or, to use the official term, in "good faith". "The witness of God is greater"! His word is one hundred percent reliable. Believers accept without question His declaration as to the true identity of Jesus and hence the incalculable value of the blood that was shed by the Son of God.
If we could be certain that v.7 was in the original text, it would be a wonderful statement of the Trinitarian position. The present writer has no expertise in ancient manuscripts, none at all. Some contend for its inclusion, and see it as being relevant to John's argument, but the majority of translators and commentators seem to feel that it was inserted in manuscripts at some point after the fourth century.
The Son of God and Eternal Life (5.10-12)
Witness to the identity of the Lord Jesus as the Son of God could not be firmer, as expressed in previous verses, for "a three-fold cord is not quickly broken" (Eccl 4.12). To those who believe that record, God gives assurance within. "The Spirit himself beareth witness with our spirit, that we are children of God" (Rom 8.16, RV). The audacity of refusing to believe a record that God has given is obvious; it is to allege that the God "that cannot lie" (Titus 1.2) is a liar! "Let God be true, but every man a liar" (Rom 3.4).
This internal confirmatory record relates to the fact that "God hath given to us eternal life", a quality and extent of life that is inexorably bound up with His Son, and hence, "He that hath the Son hath life" (v.12). Again, there are echoes from John's Gospel: "He that believeth on the Son hath everlasting life" (3.36). The converse truth must be alarming for the unbelieving sinner, "he that hath not the Son of God hath not life".
To be continued.