The Parable of the River Stones
A traveler once stood by a fast-flowing river, watching an old hermit submerge heavy boulders into the rushing water. "Why do you keep soaking those rocks?" the traveler asked. "They have been underwater for three days, yet if you crack them open right now, the very core remains bone-dry. The water washes over them, but it never alters their fundamental nature." The traveler laughed, thinking it a silly waste of time, completely unaware that he was looking directly into a mirror.