There are many similarities between 1 John and 2 John. First, in 1 John, the author deals with the same historical situation as that reflected in 2 John. He speaks of those who ‘went out from us’ and do not acknowledge ‘Jesus Christ as coming in the flesh’ (1 John 2:19, 22-23; cf. 2 John 7). Second, he brands these false teachers as antichrists, as does the elder in 2 John (1 John 2:18, 22; cf. 2 John 7). Third, he stresses the great importance of the love command, which was received at the beginning along with the gospel, just as the elder does in 2 John (1 John 3:11, 23; 4:7, 21; 5:1-4a; cf. 2 John 4-6). Fourth, the author of 1 John, like the elder, finds his joy in seeing his children walking in the truth of the gospel (1 John 1: 3-4; cf. 2 John 4).
There are also striking similarities of language, content, and style between 2 John and 3 John, and these indicate that the same elder was responsible for writing both letters: in both of them he expresses joy that the ‘children’ are ‘walking in the truth’ (2 John 4; 3 John 4); in both the addressees (the ‘chosen lady’ and Gaius respectively) are described as those whom the elder loves ‘in the truth’ (2 John 1; 3 John 1); and both conclude with virtually identical statements (2 John 12: ‘I have much to write to you, but I do not want to use paper and ink. Instead, I hope to visit you and talk with you face to face’; 3 John 13-14a: ‘I have much to write to you, but I do not want to do so with pen and ink. I hope to see you soon, and we will talk face to face’). Because of the close connections between 1 John and 2 John, and between 2 John and 3 John, there is a prima facie case for saying that the three letters were written by the same person, at about the same time, and in response to various aspects of the same crisis.
—Colin G. Kruse
Source: Colin G. Kruse, quoted from his book The Letters of John in The Pillar New Testament Commentary Series, published by Eerdmans.
