5:2. In this we know that we love the children of God: when we love God and keep his commandments.
5:3. For this is the charity of God: That we keep his commandments. And his commandments are not heavy.
5:4. For whatsoever is born of God overcometh the world. And this is the victory which overcameth the world: Our faith.
Our faith… Not a bare, speculative, or dead faith; but a faith that worketh by charity. Gal. 5.6
5:5. Who is he that overcometh the world, but he that believeth that Jesus is the Son of God?
5:6. This is he that came by water and blood, Jesus Christ: not by water only but by water and blood. And it is the Spirit which testifieth that Christ is the truth.
Came by water and blood… Not only to wash away our sins by the water of baptism, but by his own blood.
5:7. And there are Three who give testimony in heaven, the Father, the Word, and the Holy Ghost. And these three are one.
5:8. And there are three that give testimony on earth: the spirit and the water and the blood. And these three are one.
The spirit, and the water, and the blood… As the Father, the Word, and the Holy Ghost, all bear witness to Christ's divinity; so the spirit, which he yielded up, crying out with a loud voice upon the cross; and the water and blood that issued from his side, bear witness to his humanity, and are one; that is, all agree in one testimony.