Even in the event of someone not following what they were told and leeching off of other people, the Thessalonians are told to still approach them like a brother, not an enemy. Yes, they begin to distance themselves to hope that he begins to understand and see the err in his ways, but they do not consider him to be an enemy of them
Again, Paul refers to God being the centre of everything because it is him who directs our thoughts and paths. It amazes me that he has such faith that it is evident in every single thing he says that we should be relying on him to help us.