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

4:9 In this was manifested the love of God toward us, because that God sent his only begotten Son into the world, that we might live through him.