An overview of the way that John and Diotrephes act as Adam in 2 and 3 John.
The situation that John addresses in 2 John is clearly an Adam and Eve situation. Though Adam and Eve were married, Adam was to protect Eve until humanity became mature enough to eat from the Tree of the Knowledge of Good and Evil and then could be joined to God in another marriage. The theme of John-Revelation is Jesus ascending Jacob’s Ladder, choosing a Bride, defending her, and eventually marrying her. The Church is built off the water and blood that flows from Jesus’ side, and she comes under attack from a false-Trinity in Revelation. Jesus, the new Adam, defends his bride and brings her to the Bridal feast victorious over Lady Folly, Beastly Jerusalem-in-the-flesh.
John, united to Christ, is a new Adam who must protect his Bride while she matures to be able to marry God. The Elect Lady (Lady being the female form of God) has already been born and given unto the protection of the apostles (2 Corinthians 11:1-2) until her husband returns and finds her in her full maturity. A series of false teachers has arisen outside of the Church and from within the Church: these teachers deny the incarnation of Yahweh in Christ and are leading people away, quite possibly murdering them (I John 3:10-12). The false teachers have turned their eye on the Elect Lady, acting as the serpent did in the Garden by targeting the Bride rather than the husband (Revelation 12:4). John, unlike Adam, steps in to protect the Bride from the attack, telling her that the only way to be safe and be united to the Father and the Son is to “love”. Notice that this is not a new commandment, but “as [they] have heard from the beginning”. God told Adam that he would surely die, but by telling the Bride to walk in love and in the Son, they are walking in life. The Lady is not even supposed to let these false teachers into the Church, like a true Adam would not let the Serpent stay in the Garden.
The family bookends the epistle and turns on the false teachers. The only way to remain victorious over the false teachers? Loving one another and abiding in John’s teaching surrounds the teachers, overcoming them with the blood of the Lamb and the word of their testimony.
3 John is also a warning against repeating the sins of Adam. Diotrephes wants “to put himself first” and “does not acknowledge authority” by resisting the apostles who represent Christ himself. Adam similarly wanted to exalt himself by eating of the Tree of the Knowledge of Good and Evil too quickly and did not acknowledge the authority of God by listening first to the serpent.