It has been said in the Buddhist teachings that without exertion, you cannot journey on the path at all. When you are taking a holiday or a vacation, you are very inspired to wake up in the morning, because you are expecting to have a tremendous experience. Exertion is like the minute before you wake up on a holiday trip: you trust that you are going to have a good time, but you also have to put your effort into it. So true exertion is some kind of celebration and joy, which is free from laziness.
Training the Mind and Cultivating Loving Kindness, pages 70-71.