There are many styles of yoga, but they all have one thing in common – they share the same goal. Whether your yoga is a physical practice, chanting, meditation, service, or devotion, the goal is union with the divine. Yoga does not tell us what the divine is, but allows us to define it as we feel moved, even if that is to not define it at all and content ourselves with thinking of the divine as a mystery.
Yoga is the original psychology. But where modern psychology, until very recently, chose to focus almost exclusively on understanding and treating disease, yoga concerned itself with understanding and helping normal people achieve higher states of consciousness.