Trayam antarangam purvebhyah
In this verse, Patanjali says that the practice of dharana, dhyana and samadhi are more internal, compared to the first five limbs – yama, niyama, asana, pranayama and pratyahara – as explained in the sadhana pada.
These first five limbs are also called “external quest”. Yama purifies our relationship with the external world; niyama purifies our relationship with ourselves; asana cleanses the physical body; pranayama expands the energy in the body; and pratyahara withdraws the senses from their external objects.
By practicing meditation, our attention slowly moves inward. We gradually get used to sitting still, as if the body does not exist; our breath becomes so subtle that we no longer feel it; our mind no longer responds to the information received by sensory organs. As such, the boundary between inner world and out world gradually moves inward, until the body, breath and senses all become external.
As we continue the practice, we drop the body, breath and senses, we enter the “internal quest”: dharana (concentration of citta on an object), dhyana (steadfast meditation) and samadhi (oneness with the soul). The combined and simultaneous practice of dharana, dhyana and samadhi is called samyama (verse 3.4). At this stage, we let go our desires and the need to be special. We are free from being self centered. We realize that all things in the world are created for us to use, but not to possess. We begin to experience union with something much greater than ourselves. We start feeling expansion instead of feeling small. In this way, the internal quest finally leads to liberation.
However, it does not suggest that we should perfect the external quest before attempting the internal quest. Therefore, even if our asana practice is not perfected, we still can spend some time doing dharana. Being focused on asana practice is very common nowadays, in fact, some practitioners have put too much attention on asana practice. According to the scriptures, yogis and ancient masters accepted asana only as a preparation for true yogic practice. We do not deny the effect of asana on physical body; we also see the benefits of asana practice on many practitioners, especially beginners. But we need keep in mind that asana is just one limb of the eight limbs. As a serious practitioner, we should not confine our practice to asana. We should keep moving inward to explore the subtler realities.