Why did Paul write the second epistle to the Thessalonians?

In this letter, Paul focused on life in the Kingdom Age. The Thessalonians were understandably enamored with their anticipation of the triumphant return of Christ, but they had failed to recognize their significant responsibility in their own day. Paul wrote this letter to let them know that they should have been working while they waited expectantly for Christ's return. In this letter, Paul didn't want to underscore the centrality of Christ's return as he had in his first letter. His effort was rather to instruct them toward living for Christ's glory until that day.