For you yourselves know, brothers, our visit to you wasn't in vain,
Regarding Paul's alleged defense in the first paragraph, it seems to this writer, despite the near-unanimous opinion of many scholars to the contrary, that entirely too much has been made of the alleged slanders against Paul.  Brief notice was paid to this in  1 Thessalonians 1, but further pursuit of the question raises more and more doubts about the usual mode of interpretation.  Of course, there were slanders against Paul; and those intent on killing Paul would not have stopped at any device that might have been used to thwart his labors; and, from the Corinthians, it is clear enough that Paul did, now and again, address himself squarely to the problem of replying to slanderous charges.  Nevertheless, the tone of this letter is different.  At Corinth, the slanders were being promulgated by those associated with the church; but in Thessalonica there appears to have been no disruptive element within the fold at all; thus any slanders that might have come would of necessity have had to come from without; and, if we may judge from the strong terms of  1 Thessalonians 2:14-16, it was their persecution, not mere slander, that is in view.