In Tibet, we have a traditional image, the windhorse, which represents a balanced relationship between the wind and the mind. The horse represents wind and movement. On its saddle rides a precious jewel. That jewel is our mind. A jewel is a stone that is clear and reflects light. There is a solid, earthly element to it. You can pick it up in your hand, and at the same time you can see through it. These qualities represent the mind: it is both tangible and translucent. The mind is capable of the highest wisdom. It can experience love and compassion, as well as anger. It can understand history, philosophy, and mathematics—and also remember what’s on the grocery list. The mind is truly like a wish-fulfilling jewel. With an untrained mind, the thought process is said to be like a wild and blind horse: erratic and out of control. We experience the mind as moving all the time—suddenly darting off, thinking about one thing and another, being happy, being sad. If we haven’t trained our mind, the wild horse takes us wherever it wants to go. It’s not carrying a jewel on its back—it’s carrying an impaired rider. The horse itself is crazy, so it is quite a bizarre scene. By observing our own mind in meditation, we can see this dynamic at work. Especially in the beginning stages of meditation, we find it extremely challenging to control our mind. Even if we wish to control it, we have very little power to do so, like the infirm rider. We want to focus on the breathing, but the mind keeps darting off unexpectedly. That is the wild horse. The process of meditation is taming the horse so that it is in our control, while making the mind an expert rider.
― Sakyong Mipham, Running with the Mind of Meditation: Lessons for Training Body and Mind