We know that we have passed from death unto life, because we love the brethren. He that loves not his brother abides in death.
All Commentaries on 1 John 3:14 Go To 1 John 3
Augustine of Hippo
AD 430
Let none ask man: let each return to his own heart: if he find there brotherly love, let him set his mind at rest, because he is passed from death unto life. Already he is on the right hand: let him not regard that at present his glory is hidden: when the Lord shall come, then shall he appear in glory. For he has life in him, but as yet in winter; the root is alive, but the branches, so to say, are dry: within is the substance that has the life in it, within are the leaves of trees, within are the fruits: but they wait for the summer. Well then, we know that we have passed from death unto life, because we love the brethren. He that loves not, abides in death.