“What is the common factor of all the ideas in this Sūtra?
From one character to another.
Changes of mind are not based on the acquisition of new qualities,
but on those that already exist.
To bring about a desired change in the mind,
one must vary the proportion of the three basic qualities:
openness, activity and heaviness.”
– TKV Desikachar on Yoga Sūtra Chapter Four verse 2

“Powers are different arrangements
of what already exists as us.
The common factor is a redistribution of matter.”
– Paul Harvey on Yoga Sūtra Chapter Four verse 2

“TKV Desikachar taught the Viniyoga of Yoga,
or application of Yoga according
to state of life, place, time and circumstance
to optimise the student’s potential within
that situation as seen from his
own, forever evolving, innovating and
maturing, developmental teaching thread.”
– 108 Yoga Teaching Path Pointers