"Suzuki Roshi, I've been listening to your lectures for years," a student said during the question and answer time following a lecture, "but I just don't understand. Could you just please put it in a nutshell? Can you reduce Buddhism to one phrase?"
Everyone laughed. Suzuki laughed.
"Everything changes," he said. Then he asked for another question.
Explanation: One of the foremost teachings in Buddhism is that everything in life is impermanent. Suzuki Roshi (Shunryu Suzuki of Zen Mind, Beginner's Mind) is referring to this impermanence by saying "everything changes". This is a very deep teaching, but I'll attempt to sum it up in a way that can be understood and immediately helpful in a few words.
Because it encompasses everything, you can contemplate for hours on end and not realize the full magnitude of the principle of impermanence. You are impermanent, your loved ones are impermanent, your home is impermanent, even our planet is impermanent.
Why is this important? Because it teaches us that grasping onto things is one of the major reasons as to why we suffer. We need to live being aware of the ever-changing nature of reality and appreciate the present moment. It's not about letting go, it's really about not grasping in the first place.
If we can learn to live in this way, we can find peace in everyday life.