Seeing you have purified your souls in your obedience to the truth through the Spirit in sincere brotherly affection, love one another from the heart fervently:
He had before spoken of the mortification of the flesh, and of our conformity with the will of God; but he now reminds us of what God would have us to cultivate through life, that is, mutual love towards one another; for by that we testify also that we love God; and by this evidence God proves who they are who really love him. 