For even when we were with you, we commanded you this: "If anyone will not work, neither let him eat."
Although it is not stated definitely in the text, one of the things that seems to have entered into the prevalence of gross idleness Paul sought to diminish and check was a notion on the part of the idlers that Christ was coming soon and that there was no further need to work.  It is not, however, this or that motive for idleness that makes it a sin, sin being the proper name of it, no matter what the motive; and therefore Paul wisely left the motivation out of view.