He explains himself, viz. that to one who is born of God his commandments are not grievous, because such a one, in that divine birth, hath received a life and nature that makes him far superior to this world, exalts him above it, makes him victorious over the worldly spirit, \as 1 John 4:4\ over all worldly desires, and fears, and hopes, and joys, which are the great hinderances of our obedience to God. This is the victory; i.e. the instrument, the weapon, by which they overcome, and which virtually includes in itself this victory over the world, as effects are included in the power of their cause, is their faith, that principle which in their regeneration (as above) is implanted in them.
Related Commentaries of 1 John 5:4
1 John 5:4
4 For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith.