Chop Wood, Carry Water.
I first heard this while reading Ryan Holiday's "Stillness is the Key." As soon as I heard it, I wanted it to guide my life.
The simplest way I have seen it explained is as a Zen mantra. The idea is that you reach enlightenment by chopping wood and carrying water. And once you become enlightened all there is to do is chop wood and carry water.
In other words, life is all about doing hard work day by day. Doing that will eventually get you to a point of achievement. But when you get there, you will realize that you have to keep going. You have to keep chopping wood and carrying water.