Yoga Sutra II.40

Kate Holcombe writes that, "In verse II.40 of the Yoga Sutra, Patanjali speaks of saucha (purity or cleanliness) as a means to help you reach a state of yoga, or focused concentration."

It's a paradox though because as you clean and purify the body through yoga and pure thoughts, there is decay.

But that is the teaching. You lovingly care and tend to the body even as it ages and weakens and this makes the soul grow stronger.

Kate Holcombe says it better than I, "In time, you see that no matter how diligent you are, your surroundings and even your body are decaying every moment, whereas your inner or true, Self is permanent and unchanging this realization gradually leads you to focus your attention inward..and connection with your higher power."