In plain words
The man of today is educated. In this, in particular, is a consciousness called the principle of the Ātma. Without it, humanness is nothing but inert, nothing but lifeless! We may well call it artificial. They said that learning must be joined with tapas. Tapas does not mean leaving house and home, leaving wife and children, giving up property and possessions, going off to the forest, closing the nose and heaving the flanks. Tapas is nothing but the oneness of the guṇas, sattva, rajas and tamas. Not only this: looked at subtly, it is the oneness of the karmas of mind, word and body! This is what they called ‘The proper study of mankind is man’. They said that to make our resolve, our word and our deed one is true tapas. To think one thing in Manas, say another in words and do yet another in action: they said this is the mark of wickedness. To follow neither of these two and behave only as it pleases one's own intellect is ‘tamas’, they said. So only when we transform the conduct of the body into something sacred through the qualities of the Ātma does this become the oneness of learning and tapas. This itself is niyama, they said. The essence of everything is held in yama and niyama alone, the chief limbs of Aṣṭāṅga Yoga. In yama and niyama themselves, at the very first, there is a great deal of hardship. Once we have achieved these two, all the yogas become very easy for us to know.
Showing indifference to all objects is āsana
The third is āsana. In yoga there are many āsanas, such as padmāsana, śīrṣāsana and mayūrāsana. These are physical forms. Āsana is really this: showing indifference to all objects. We must cultivate a feeling of indifference towards all things. Some day or other these will perish. Some day or other, either we must give them up or they us; there is no escaping it. It teaches that to give up, gradually and knowingly, what must be given up some day is the best way.