The Iyengar approach to yoga is firmly based on the traditional eight limbs of yoga expounded by Patanjali in his classic treatise, The Yoga Sutras, written over 2,500 years ago.
Patanjali, a sage and a scholar, is credited for writing the Yoga Sutras, the first written statement of yogic philosophy. Before that, yoga followed an oral tradition, passed on personally from teacher to student. Patanjali is also credited for classical texts on Sanskrit grammar and medicine.
In 196 succinct aphorisms (phrases), Patanjali's Yoga Sutras describe the working of the mind and emotions, and the path to fulfillment.
In the second sutra of the Yoga Sutras Patanjali defines Yoga as "the stilling of the fluctuations of the mind". This famous phrase encapsulates both the practice and the ultimate aim of yoga.
In the practice of Yoga, the Yoga Sutras of Patanjali acts as a guide and at the same time the experiences and lessons learned through the practice become a testament to the wisdom encapsulated in the text. Through the practice, one also understands and verifies the universal teachings expounded in other ancient texts about yoga, man and the universe - such as the Bhagavad Gita.
The introduction to Light on Yoga by BKS Iyengar is an excellent source for understanding the philosophy behind Yoga practice.
“Yoga means union. The union of the individual soul with the Universal Spirit is yoga. But this is too abstract a notion to be easily understood, so for our level of understanding I say that yoga is the union of body with the mind and of mind with the soul”.
– BKS Iyengar, Tree of Yoga.