Albert Barnes Commentary 2 Corinthians 2:12

"Now when I came to Troas for the gospel of Christ, and when a door was opened unto me in the Lord," — 2 Corinthians 2:12 (ASV)

Furthermore. But, (de.) This particle is properly adversative; but frequently denotes transition and serves to introduce something else, whether opposite to what precedes, or simply continuative or explanatory. Here it is designed to continue or explain the statement previously made of his deep affection for the church and his interest in its affairs. He therefore tells them that when he came to Troas, he was favored there with great success and was engaged in a manner most likely of all others to interest his feelings and give him joy. Yet, he was deeply distressed because he had not heard from them as he expected. Indeed, so deep was his anxiety that he left Troas and went into Macedonia.

When I came to Troas. This was a city of Phrygia or Mysia, on the Hellespont, between Troy on the north and Assos on the south (Acts 16:8). It was on the regular route from Ephesus to Macedonia. Paul took that route because on his journey to Macedonia he had resolved, for the reasons stated above, not to go to Corinth.

To preach Christ's gospel. (Greek, "For (eis) the gospel of Christ;" that is, on account of his gospel, or to promote it). He does not say why he selected Troas, or the region of the Troad (Acts 16:8), as the field of his labours. It is probable that he was waiting there to hear from Corinth by Titus, and while there, he resolved not to be idle but to make the gospel known as much as possible.

And a door was opened unto me (1 Corinthians 16:9). There was an opportunity for doing good, and the people were disposed to hear the gospel. This was a work in which Paul delighted to engage and in which he usually found his highest comfort. It was, of all things, the most adapted to promote his happiness.