"No rest for the wicked" is an idiom originating from the Book of Isaiah (as Peachey's links indicate). It is used when somebody is complaining that they have a lot of work to do.

The actual phrase is "no rest for the wicked". Your sentence actually means the opposite. "No rest for the wicked" is a comment to say when you are very busy. It suggests that what you are doing is mischievous, and there is no end to mischief (therefore, whoever makes mischief must be very busy). ;) Update: Hi again! I've had a check, here's a couple of links: http://en.wikipedia.org/wiki/No_rest_for_the_wicked http://www.phrases.org.uk/meanings/257500.html (which means the wicked shall be tormented... with being busy?)