The phrase "idle hands" means that when you have nothing to do or are not working, you may get yourself into trouble or engage in undesirable activities. Full definition
Once the job is done, you don't have to keep them on the payroll, ensuring that your business isn't paying for idle hands. (entrepreneur.com)
While that was the immediate draw and my full intention behind this dish, I found myself with idle hands and decided to let it cook on the stove. (solidgoldeats.com)
No other intellectual and moral virtue can bring together the immense number of idle hands with the immense amounts of work still to be done to improve the living conditions of the poor. (firstthings.com)