Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
3 John 1:1
The Third Epistle encourages the believer to the exercise of hospitality, whether towards the known brethren or strangers, and to all benevolent care in furthering their journey when departing, provided that they come with the truth and for the truth's sake without salary or provision. Gaius received them as it appears. and was helpful to them both in his own house and on their journey. Diotrephes, on the contrary, did not love these strangers, who went about, it is said, without a formal mission and without any visible means of subsistence. They had gone forth for the Lord's sake and had received nothing from the Gentiles. If they in reality came out of love to that name, one did well to receive them.
Again the apostle insists on the truth, as characterising real love: "Whom I love in the truth," he says to Gaius. He rejoiced when the brethren (those, I imagine, whom Gaius had received into his house and helped on their journey) testified of the truth that was in him, as in effect he walked in the truth. The apostle had no greater joy than that of hearing that his children walked in the truth. In receiving those who went forth to preach the truth, they helped the truth itself; they were co-workers with it. Diotrephes would have nothing to do with this; he not only refused to receive these itinerant preachers, but excommunicated those who did so. He claimed authority for himself. The apostle would remember it. It is their duty to do good. "He that doeth good is of God."
He goes so far, with regard to the truth, as to say, that the truth itself bore witness to Demetrius. I suppose that the latter had propagated it, and that the establishment and confirmation of the truth every where-at least where he had laboured was a testimony with regard to himself.
This insistence on the truth, as the test for the last days, is very remarkable; and so is this preaching itinerancy' by persons who took nothing of the Gentiles when they came forth, leaving it to God to cause them to be received of those who had the truth at heart, the truth being their only passport among Christians, and the only means by which the apostle could guard the faithful. It appears that they were of the Jewish race, for he says, "receiving nothing of the Gentiles," the apostle thus making the distinction. I notice this, because, if it be so, the force of the expression "and not for ours only" (l Joh 2:2) becomes simple and evident, which it is not to every one. The apostle, as Paul does, makes the difference of 'us', Jews, though one in Christ. We may also remark that the apostle addressed the assembly, and not Diotrephes, its head; and that it was this leader who loving preeminence, resisted the apostle's words which the assembly, as it appears, were not inclined to do.
Gaius persevered in his godly course, in spite of the ecclesiastical authority (whatever may have been its right or pretended right) which Diotrephes evidently exercised: for he cast persons out of the assembly.
When the apostle came, he would (like Paul) manifest his real power. He did not own in himself an ecclesiastical authority to remedy these things by a command. These Epistles are very remarkable in this respect. With regard to those who went about preaching, the only means he had, even in the case of a woman, was to call her attention to the truth. The authority of the preacher lay altogether in that. His competency was another matter. The apostle knew no authority which sanctioned their mission, the absence of which would prove it to be false or unauthorised. The whole question of their reception lay in the doctrine which they brought. The apostle had no other way to judge of the authority of their mission: there was then no other; for, had there been any that authority would have flowed from him. He would have been able to say, "Where are the proofs of their mission?" He knew none but this do they bring the truth? If not, do not salute them. If they bring the truth, you do well to receive them, in spite of all the Diotrephes in the world.