The direct external evidence that this as well as the following Epistle was written by St. John the Apostle, is fully attested to in the Church Fathers. Extensive references to both Epistles are found in early patristic literature to prove their authorship and authenticity. We have a number of testimonies in the citation of passages obviously derived from either the Second or the Third Epistle. Again, the vocabulary throughout is precisely that which is found in the Gospel of Saint John and in the First Epistle.
One of the pretended claims of the Papacy, to be able to forgive sin – when only God can forgive sin, is emphatically not allowed here where St. John tells us how we are forgiven: John 1:1 That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, of the word of life: 2 For the life was manifested; and we have seen and do bear witness, and declare unto you the life eternal, which was with the Father, and hath appeared to us: 3 That which we have seen and have heard, we declare unto you, that you also may have fellowship with us, and our fellowship may be with the Father, and with his Son Jesus Christ. 4 And these things we write to you, that you may rejoice, and your joy may be full. 5 And this is the declaration which we have heard from him, and declare unto you: That God is light, and in him there is no darkness. 6 If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth. 7 But if we walk in the light, as he also is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin. 8 If we say that we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, He is faithful and just, to forgive us our sins, and to cleanse us from all iniquity.
See: God, His Infinite Existence and Governing Presence in His creation and His forgiveness of sin
See these links: BISHOPS, CATHOLICS, COMMUNES, COMMUNES ET ECCLESIASTICOS, ECCLESIASTICS,ECCLESIASTICS AND COMMUNES, EUCHARIST, HIERUS, HORUS, ISIS, PRESBYTEROS,PRIESTHOOD, ST. CLEMENT OF ROME, ΚΑΘΟΛΙΚΟΎΣ, Jesus Christ in the Dura-Europos house churches
See the Didache for the establishment of house churches and their self rule as the norm for the Church at all times in perpetuity - to remain as this until and including at the time of the Second Coming of Our Lord and Saviour Jesus Christ.
- The Epistle of St. Polycarp (disciple of St. John the Apostle) to the Philippians, Chapter VI.-The Duties of Presbyters and Others.
- St. Irenaeus Against Heresies Book I Chapter XXIII - Simon Magus (See Acts Chapter 8 Simon the Magician) attempts to be called Holy Father and be head over the Church, first heretic attempting to be "Pope"
- St. Hippolytus - Refutation of all Heresies Book IX Chapter VII - Callistus and Zephrynus attempting to be universal head over the Church and attempting to claim they can forgive sin when only God can
- Pope St. Gregory the Great - Epistle LXVIII - Pestiferous - Universal Earthly Bishop = Forerunner of Antichrist