Text 12
sarva-dvarani samyamya
mano hridi nirudhya ca
murdhny adhayatmanah pranam
asthito yoga-dharanam
Translation
The yogic situation is that of detachment from all sensual engagements. Closing all the doors of the senses and fixing the mind on the heart and the life air at the top of the head, one establishes himself in yoga.
Commentary by Srila Prabhupada
To practice yoga as suggested here, one first has to close the doors of all sense enjoyment. This practice is called pratyahara, or withdrawing the senses from the sense objects. The sense organs for acquiring knowledge—the eyes, ears, nose, tongue and touch—should be fully controlled and should not be allowed to engage in self-gratification. In this way the mind focuses on the Supersoul in the heart, and the life force is raised to the top of the head. In the Sixth Chapter this process is described in detail. But as mentioned before, this practice is not practical in this age. The best process is Krishna consciousness. If one is always able to fix his mind on Krishna in devotional service, it is very easy for him to remain in an undisturbed transcendental trance, or in samadhi.
Commentary by Sri Visvanatha Cakravarti Thakur
Please see text 13 for Sri Visvanatha Cakravarti Thakur's combined commentary to texts 12 and 13.