Demetrius has received a good testimony from everyone, and from the truth itself. We also testify for him, and you know that our testimony is true.
I. Demetrius, on the other hand, has a good report from all and of the truth itself. John and others also bear witness to his character, and Gaius can trust this testimony. Demetrius was likely well known to both John’s church and Gaius's. II. John closes the letter expressing a desire to see Gaius soon and wishing him peace.
Commenting on 3 John 1:12-14
Demetrius hath good report of all men, This man was of a quite different cast from Diotrephes, and therefore the apostle makes mention of him to Gaius, to be followed by him, and not the other; he was either the same with Demas, which is a contraction of this name, or the person that John sent from Ephesus with this letter: we read of an...
Verse 12. Demetrius hath good report of all men. Little is known of Demetrius. Locke supposes that he resided near the place where the author of this epistle lived, and was connected with the church there, and was probably the bearer of this epistle.