For you yourselves know, brothers, our visit to you wasn't in vain,
that it was not in vain: The changes wrought in the lives of the Thessalonian converts are dramatic (1:9). Paul’s preaching at Thessalonica, though of short duration, has not been a failure. It has been highly effective, and the results are permanent, the perfect tense of the verb indicating a continuing result. The fact that Paul leaves a thriving congregation at Thessalonica is convincing evidence that his entrance is not vain.