Verse 18. And we have sent with him the brother. It has been generally supposed that this anonymous brother was Luke. Some have supposed, however, that it was Mark; others that it was Silas or Barnabas. It is impossible to determine with certainty who it was; nor is it material to know. Whoever it was, it was some one well known, in whom the church at Corinth could have entire confidence. It is remarkable that though Paul mentions him again, 2 Co 12:18, he does it also in the same manner, without specifying his name. The only circumstances that can throw any light on this are,

(1.) that Luke was the companion and intimate friend of Paul, and attended him in his travels. From Ac 16:10,11, where Luke uses the term "we," it appears that he was with Paul when he first went into Macedonia; and, from Ac 16:16, it is clear that he went with Paul to Philippi. From Ac 17:1, where Luke alters his style, and uses the term "they," it is evident that he did not accompany Paul and Silas when they went to Thessalonica, but either remained at Philippi, or departed to some other place, he did not join them again until they went to Troas, on the way to Jerusalem, Ac 20:5. In what manner Luke spent the interval is not known. Macknight supposes that it might have been in multiplying copies of his gospel for the use of the churches. Perhaps also he might have been engaged in preaching, and in services like that in the case before us.

(2.) It seems probable that Luke is the person referred to by the phrase, "whose praise is in the gospel throughout all the churches." This would be more likely to be applied to one who had written a gospel, or a life of the Redeemer, that had been extensively circulated, than to any other person. Still it is by no means certain that he is the person here referred to, nor is it of material consequence.

Whose praise. Who is well known and highly esteemed.

Is in the gospel. Either for writing the gospel, or for preaching the gospel. The Greek will bear either construction. In some way he was celebrated for making known the truths of the gospel.