For this reason, Paul found it necessary to write to the Thessalonian Christians a Second Epistle — shortly after sending them the First Epistle. Hopefully, the first had convinced them that there would be no rapture of the saints from out of this wicked World — and no History which would thereafter continue among the wicked on an all-evil Earth.
But now in his Second Epistle, he thought it imperative to explain to the Thessalonian Christians very clearly — that they should not even expect a soon return of Christ at all. Instead, they should now rather work hard and long to advance His Kingdom right here on Earth — even in spite of numerous then-increasing persecutions.