In my reading for my Yogateacher training I stumbled over the parable of the chariot in the Upanishads.
Here you can find verse 1.3.3 to 1.3.6
3. Know the âtman as the lord of the chariot, the body as only the chariot, know also intelligence as the driver; know the minds as the reins.
4. The senses, they say, are the horses; the objects which they perceive, the way; the âtman, the senses and the mind combined, the intelligent call the enjoyer.
5. But of him who is not possessed of discrimination, and whose mind is always uncontrolled, the senses are not controllable as vicious horses of a driver.
6. But of him who knows and has a mind always controlled, the senses are always controllable as the good horses of the driver.