Basically Yoga means “union”. It is the Sanskrit ancestor of the English word “yoke”. Hence, it comes to mean a method of spiritual union. A yoga is a method any one of the many by which an individual may become united with the Godhead, the Reality which underlies this apparent, ephemeral universe. To achieve such union is to reach the state of perfect yoga. Christianity has a corresponding term, the mystic union” which expresses a similar idea.
Bhoja, one of the classical commentators on these aphorisms, defines Patanjali’s use of the word yoga as “an effort to separate the Atman from the non-Atman (the apparent)
One who practices yoga is called a yogi.
There are five kinds of thought waves – some painful, others not painful.
A painful wave, according to Patanjali’s us of the term, is not necessarily a wave which seems painful when it first arises in the mind it is a wave which brings with it an increased degree of ignorance, addiction and bondage. Similarly, a wave which seems painful at first may actually belong to the category of those which are “not painful” provided that it impels the mind toward greater freedom and knowledge. For example, Patanjali would describe a lustful thought-wave as “painful”, because lust, even when pleasantly satisfied, causes addiction, jealousy and bondage to the person desired. A wave of pity, on the other hand would be described as “not painful. Because pity is an unselfish emotion which loosens the bonds of our own egotism. We may suffer deeply when we see others suffering, but our pity will teach us understanding and, hence, freedom.
This distinction between the two kinds of thought-waves is very important when we come to the actual practice of yoga discipline. For the thought-waves cannot all be controlled at once. First, we have to overcome the painful thought waves by raising waves which are not painful. To our thoughts of anger, desire and delusion we must oppose thoughts of love, generosity and truth. Only much later, when the painful thought waves have been completely stilled, can we proceed to the second stage of discipline, the stilling of the not painful waves which we have deliberately created.