1 John 3:14

Love for other Christians shows the presence of new life in us and is a secondary ground for assurance (cf. 1 John 5:13). "Death" and "life" are two vastly different spheres of existence. The contrast shows the great change that has taken place in the believer’s life. The one who does not love at all is the person who is abiding in death rather than in eternal life. John made the case extreme to make his point clear. His contrasts are death and life, hatred and love, darkness and light.