16:13-18 A Christian is always in danger, therefore should ever be on the watch. He should be fixed in the faith of the gospel, and never desert or give it up. By this faith alone he will be able to keep his ground in an hour of temptation. Christians should be careful that charity not only reigns in their hearts, but shines in their lives. There is a great difference between Christian firmness and feverish warmth and transport. The apostle gave particular directions as to some who served the cause of Christ among them. Those who serve the saints, those who desire the honour of the churches, and to remove reproaches from them, are to be thought much of, and loved. They should willingly acknowledge the worth of such, and all who laboured with or helped the apostle.

17. Fortunatus … Achaicus—probably of Stephanas' household.

that … lacking on your part—So far as you were unable yourselves to "refresh my spirit," in that you are absent from me, "they have supplied" by coming to me from you, and so supplying the means of intercourse between you and me. They seem to have carried this letter back; see the subscription below: hence the exhortations, 1Co 16:16, 18, as though they would be at Corinth when the Epistle arrived.