The phrase literally means that if you want to have little time to spare, don't do anything.
They say that this quote belongs to A.P Chekhov. I guess we cannot be 100% sure what meaning he had put in this phrase. We can suppose that people who don't do anything, never have enough time & always complain for the lack of time. On the contrary people that have a lot of tasks to do, tend to organize themselves better and manage to accomplish much more.
So I guess he was referring to procrastination.