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 5

5:10 He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son.