Sharing knowledge is one of the most important and critical aspects of our lives. When a body drinks, what it does is helps the food be distributed throughout the parts of the body. When a person grinds his food down with his teeth, the food itself which the person does eat, undergoes a change. The water remains the same as it was originally and does not undergo any transformation. Similarly, a student repeats what he has learned from his teacher or others. He must impart those teachings exactly as he received them, without changing them in any way. Just like water.