3 John 1:12

12. of all men--who have had opportunity of knowing his character. of the truth itself--The Gospel standard of truth bears witness to him that he walks conformably to it, in acts of real love, hospitality to the brethren (in contrast to Diotrephes), &c. Compare Joh 3:21 "He that doeth truth cometh to the light, that his deeds may be made manifest that they are wrought in God." we also--besides the testimony of "all men," and "of the truth itself." ye know--The oldest manuscripts read, "thou knowest."

Robert Jamieson, A. R. Fausset & David Brown, 1871 · public domain

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. It is impossible to determine with certainty on this point, but there is one circumstance which seems to make it probable that he was a member of the same church with Gaius, and had united with him in showing Christian hospitality to these strangers. It is the use of the phrase "hath good report of all," implying that some testimony was borne to his character beyond what the writer personally knew. It is possible, indeed, that the writer would have used this term respecting him if he lived in the same place with himself, as expressing the fact that he bore a good character, but it is a phrase which would be more appropriately used if we suppose that he was a member of the same church with Gaius, and that John means to say that an honourable testimony was borne of his character by all those brethren, and by all others as far as he knew.

And of the truth itself. Not only by men, who might possibly be deceived in the estimate of character, but by fact. It was not merely a reputation founded on what appeared in his conduct, but in truth and reality. His deportment, his life, his deeds of benevolence, all concurred with the testimony which was borne by men to the excellency of his character. There is, perhaps, particular reference here to his kind and hospitable treatment of those brethren.

Yea, and we also bear record. John himself had personally known him. He had evidently visited the place where he resided on some former occasion, and could now add his own testimony, which no one would call in question, to his excellent character.

And ye know that our record is true. This is in the manner of John, who always spoke of himself as having such a character for truth that no one who knew him would call it in question. Every Christian should have such a character; every man might if he would. Compare Jn 19:35, 21:24.

(+) "all men" It is well spoken of by all" (++) "of the truth itself" "By" (&) "record" "witness"

Albert Barnes, 1834 · public domain

Verse 12 Demetrius hath good report - Perhaps another member of the Church where Caius was; or he might have been one of those whom the apostle recommends to Caius; or, possibly, the bearer of this letter from John to Caius. He seems to have been an excellent person: all testified of his righteousness; the truth - Christianity, itself bore testimony to him; and the apostles themselves added theirs also.

Adam Clarke, 1831 · public domain