The Epistles of John, assigned to the writer of the Fourth Gospel and the Revelation, testify that God is love and that love is the test of religion. Second John is written to “the elect lady and her children,” probably a church; Third John is addressed to “the beloved Gaius.”

1 John 4

4:2 Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God: