The elder unto the wellbeloved Gaius, whom I love in the truth. The elder - See on the first verse of the preceding epistle (2 John 1:1 (note), and also the preface.
The well-beloved Gaius - Γαιος Gaius, is the Greek mode of writing the Roman name Caius; and thus it should be rendered in European languages.
Several persons of the name of Caius occur in the New Testament.
1. In the Epistle to the Romans, Romans 16:23, St. Paul mentions a Caius who lived at Corinth, whom he calls his host, and the host of the whole Church.
2. In 1 Corinthians 1:14, St. Paul mentions a Caius who lived at Corinth, whom he had baptized; but this is probably the same with the above.
3. In Acts 19:29, mention is made of a Caius who was a native of Macedonia, who accompanied St. Paul, and spent some time with him at Ephesus. This is probably a different person from the preceding; for the description given of the Caius who lived at Corinth, and was the host of the whole Church there, does not accord with the description of the Macedonian Caius, who, in the very same year, traveled with St. Paul, and was with him at Ephesus.
4. In Acts 20:4, we meet a Caius of Derbe, who was likewise a fellow traveler of St. Paul. This person cannot be the Corinthian Caius, for the host of the Church at Corinth would hardly leave that city to travel into Asia: and he is clearly distinguishable from the Macedonian Caius by the epithet Δερβαιος, of Derbe.
5. And lastly, there is the Caius who is mentioned here, and who is thought by some critics to be different from all the above; for, in writing to him, St. John ranks him among his children, which seems, according to them, to intimate that he was converted by this apostle.
Now, whether this Caius was one of the persons just mentioned, or whether he was different from them all, is difficult to determine; because Caius was a very common name. Yet if we may judge from the similarity of character, it is not improbable that he was the Caius who lived at Corinth, and who is styled by St. Paul the host of the whole Church; for hospitality to his Christian brethren was the leading feature in the character of this Caius to whom St. John wrote, and it is on this very account that he is commended by the apostle. Besides, St. John's friend lived in a place where this apostle had in Diotrephes a very ambitious and tyrannical adversary; and that there were men of this description at Corinth is evident enough from the two epistles to the Corinthians, though St. Paul has not mentioned their names. See Michaelis.
The probability of this Caius being the same with the Corinthian Caius has suggested the thought that this epistle was sent to Corinth; and consequently that the second epistle was sent to some place in the neighborhood of that city. But I think the distance between Ephesus, where St. John resided, and Corinth, was too considerable for such an aged man as St. John is represented to be to travel, whether by land or water. If he went by land, he must traverse a great part of Asia, go through Thrace, Macedonia, Thessaly, and down through Greece, to the Morea, a most tedious and difficult journey. If he went by water, he must cross the Aegean Sea, and navigate among the Cyclades Islands, which was always a dangerous voyage. Now as the apostle promises, both in the second and in this epistle, to see the persons shortly to whom he wrote, I take it for granted that they could not have lived at Corinth, or anywhere in the vicinity of that city. That St. John took such a voyage Michaelis thinks probable; "for since Corinth lay almost opposite to Ephesus, and St. John, from his former occupation, before he became an apostle, was accustomed to the sea, it is not improbable that the journey or voyage which he proposed to make was from Ephesus to Corinth."
In answer to this I would just observe,
1. That the voyage was too long and dangerous for a man at John's advanced age to think of taking.
2. That John had never been accustomed to any such sea as the Aegean, for the sea of Galilee, or sea of Tiberias, on which, as a fisherman, he got his bread, was only an inconsiderable fresh water lake; and his acquaintance with it could give him very few advantages for the navigation of the Aegean Sea, and the danger of coasting the numerous islands dispersed through it.