sattvam rajas tama iti
gunah prakriti-sambhavah
nibadhnanti maha-baho
dehe dehinam avyayam

"Material nature consists of three modes—goodness, passion and ignorance. When the eternal living entity comes in contact with nature, O mighty-armed Arjuna, he becomes conditioned by these modes."

Nibadhnanti = is bonded. Avyayam = birthless in natural state or without the three qualities in natural state, dehinam = atman, dehe = in body, nibadhnanti = bonded. In its natural state atman has no births or deaths, nor is associated with satvam, rajas and tamas qualities; yet, atman is bonded in a body by these qualities in samsaram. Where are those Three qualities? Are they stuck with atman or with body? Could we see them? Unless we know their place or origin, how can we destroy them? Iti = these, satvam, rajas, tama = satvam, rajas and tamas, gunah = qualities, prakruti-sambhava = always associated with prakruti. They are integral part of prakruti, which transforms into body. Therefore, these Three qualities are inseparable from our bodies. Now we will see the replies for the questions raised. Karma gives raise to birth in a body; so after birth that karma is spent and is over. After birth, having spent karma, atman should be in its natural state. Why it is not so? Because, birth is in a body, which has the Three qualities as integral part. Therefore, atman is influenced by the body and the Three qualities, and so atman desires to experience pleasures and pains. The desire impels to do various actions. These actions are responsible for the consequent punya/papa. These induce rebirths on and on. Thus the integral satvam, rajas and tamas qualities of prakruti, are in body and cause further papa/punya. Prakruti is the basic raw material and its qualities are seen in body. It is like, for example, if we make a pot out of clay of particular color, same color is seen in pot. The color of the thread is reflected in the cloth and garments. We should remember prakruti is not these Three qualities, but prakruti's nature. The five perceptions like taste, smell, etc. are also qualities of prakruti, but of temporary nature. Whereas satvam, rajas and tamas are permanently in prakruti and can never be separated. Though these three qualities can never be seen, their effects can be felt. If satvam is predominant at any time, the person would be very bright; rajas would make him to increase desire. Like poison's nature of killing is not visible, here also effects only will reveal the presence of these three qualities. Thus the inseparable three qualities in the body, induce one to act and acquire papa/punya and consequent births. The Lord is going to explain further each quality. Swami Doodayacharya breathed his last in Srimushnam, on aippasi -ashtami, in 1607.