We have been patient with you over the last few weeks. We've tolerated your lack of drive and initiative. We've accepted your laziness, and have even enjoyed the time off ourselves.
However, it is now time to get things back in gear. If you won't support yourself in your own goals and desires, we're not going to stick around either. We'll slowly reduce our influence and contribution to you over time, and the benefits that you reap from our presence will be gone. You don't have a choice in the matter... this is simply the way this works.
So, while we have long-term goals and would appreciate some returned committment, we're willing to accept a short term objective: You must go to the gym today.