The marks of true children of God are a correct view of Christ's person, love to God and one another, obedience to God's commandment, and faith, this being the victorious principle by which the world is overcome in its efforts to tempt us not to obey God.
1 John 5:1 a. See 1 John 4:2 *. The full belief in Jesus as a Divine-human being is meant, as also in 1 John 5:5.
1 John 5:2. when we love God: the argument seems the opposite of 1 John 4:20, but the problem is being approached from a new point of view, and John is arguing that love of the parent involves also love of those who, like ourselves, have been begotten of Him.
1 John 5:3 a. Love and obedience are bound up with each other.
1 John 5:4. the world: i.e. the anti-Christian environment (1 John 2:15 *, 1 John 4:3) whose evil influences tend to make obedience difficult, yet not impossible to those who, being begotten of God, receive a plentiful supply of His grace. hath overcome: the change of tense may arise from the victory, though in process of being won, being regarded as assured (EGT). If a victory already past be meant, the reference may be to the triumph over the false teachers (1 John 4:4), or to the victorious stand which the Church from its foundation had, in virtue of its faith, made against the world.