Life is like a ship upon an endless sea.
Everywhere there are always waves, ready to strike ferociously. Whether we want it or not, even though we try to avoid it as much as we can, sooner or later the ship would hit some of them and the hull would suffer. It will be thrown by winds, its sails shredded to nothingness.
Every single damage will cause the ship to halt. And every single wound will make the repairs better, reinforcing it so the same waves would not hurt it anymore. The ship will get stronger and stronger every time. Thus, the ship will keep moving.
And if the ship has come to a full stop, then it means that it has been wavestruck so much, that it eventually sunk. When it comes into those, a ship can never stand again to continue its voyage. That is why there are other ships around, so that they can reel our ship from the depths of the sea, and push us forward, again drifting in the endless sea.