Once when I was teaching about life and death a swami quietly came in and sat with my students. I thought he was a beginner, so I treated him as I treated the others. While the others were carefully taking notes, he only smiled, and that annoyed me.

I finally asked, “Are you listening to me?” He said, “You are only talking, but I can demonstrate mastery over life and death. Bring me an ant.” A large ant was brought. He cut it into three pieces and separated them. Then he closed his eyes and sat motionlessly. After a moment the three parts moved toward each other. They joined, and the revived ant scurried away.

I knew it was not hypnosis or anything like that. I felt tiny before that swami. And it embarrassed me before my students because I only knew the scriptures without a firsthand understanding and mastery of life and death.

I asked, “Where did you learn that?” He said, “Your master taught me.” At that, I became angry with my master and immediately went to him. Seeing me he asked, “What happened? Why are you once again allowing anger to control you? You are still a slave to your violent emotions.” I said, “You teach others things which you don’t teach me. Why?”

He looked at me and said, “I have taught you many things—but you don’t practice. That is not my fault! All these achievements depend on practice, not just on verbal knowledge of them. If you know all about the piano but don’t practice, you will never create music. Knowing is useless without practice. Knowing is mere information. Practice gives direct experience, which alone is valid knowledge.”

source: “Living with the Himalayan Masters” by Swami Rama