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

4:12 No man hath seen God at any time. If we love one another, God dwelleth in us, and his love is perfected in us.