The ocean will purify them without complaint. Instructors must correct bad students without complaining. Men must protect the ocean from man-made toxic chemicals. We must protect the dojo from delinquency. The brook and river waters are rough, but the lake and ocean are calm because of their depth.
Beginners are rough, but someday become calm.
Rough water cannot be seen through. We will be able to see through calm water. Not all calm water is clear, but someday it will be so. Calmness of mind takes time. Only then we will be able to see the truth.