[B]I, 32 Tat pratisedha artham eka tattva abyasah
In order to prevent
these obstacles from arising,
you should habituate
yourself to meditation
upon a single principle.[/B]
Swami Satchidananda advises to spend some time on deciding on an object for concentration to achieve the goal of one-pointed concentration or dharana. Once this goal is achieved, the object is left behind as the mind transcends itself. He recommends that once the object is selected, it should remain the focus of attention or else the effort will be dissipated. He likens it to digging a well ? instead of abandoning the well when hard rock is encountered, one should persevere and use dynamite to dig deeper ! To abandon that site and dig elsewhere does not guarantee that one will not encounter hard rock but will only yield several shallow wells.
Iyengar interprets this sutra to mean to focus on devotion and surrender to God as the single principle. However, he believes that this way is only possible for enlightened souls like Ramana Maharshi, Sri Ramakrishna Parmahasa, Mahatma Gandhi. In contrast, Sw. Satchidananda states that one should choose whatever object that inspires the sadhaka because the object is only the a symbol of the goal one wishes to achieve.
Happy digging !
Iyengar, B.K.S., Light on the Yoga Sutras of Patanjali. New Delhi, India: Harper Collins Publications India. 1993
Swami Satchidananda, The Yoga Sutras of Patanjali. Buckingham, VA: Integral Yoga Publications. 2004
Stiles, M., Yoga Sutras of Patanjali. Boston, MA: Red Wheel/Weiser LLC. 2002.