Book 3 Sutra 2
3.2 Unbroken continuation of that mental ability is meditation.
I personally love this part of the Yoga Sutras. It's time to get down into the basics of what meditation really is. In this Sutra and may more to follow, we see the state of mind that is needed in order to gain and maintain the technical state of meditation.
I use the term "technical state of meditation" because the term is so broadly used in western society. What do we consider meditation? Some of us like to use imagdy, some like to star into a candle, some visualize and others consider running as a form of meditation. Don't run and meditation, you will break you ankle or worse, maybe fall into a hive of killer bees. We have them here in Arizona, and they don't like anything, but they really geek out on meditating runners that fall into their hives.
So when when all the thoughts have been categorized and we begin to break our conscious associations with them, it state of meditation is like riding a bike. I like to describe it as a state between wake and sleep, relaxation and focus. Try as I may to explain it, true yogic meditation is something that needs to "bee" experienced. Now that you have laughed so hard at my pun you fell off the sofa and on to the floor, give it a try. See if you can stop your thoughts. I'm sure your can't, and that is ok. The active process of stopping your thoughts is, in actually a passive process of paying attention to them in order to get rid of them.