Sastras are meant to benefit the jivatmas caught in samsara. In every birth the jivatma is compelled to act and this entails his experiencing the fruits of his action. So whatever birth the jivatma takes, he automatically becomes the doer and the enjoyer.
Among the many sutras in the Brahmasutra that discuss the identity of the soul, the sutra 'Karta Sastrarthavatvat,' establishes that agency and enjoyment are for the soul, though this is not its nature, pointed out Sri Mani Dravid Sastrigal in a discourse. All the Vedic injunctions and dharmas prescribed for the jivatma are for the individual deha dharma. These instil the knowledge to do certain acts and refrain from certain others. If the jivatma has to experience karma phala, he needs the sarira, indriyas and manas. Sarira means the sthula and the sukshma sarira with which the jivatma interacts with the external world. The actions are done by the sthula and sukshma sarira, or by the mind or by using the sense organs. For instance when one speaks he uses the organ of speech. All punya and papa are owing to these sadanas. With all these he is the karta.
According to Sankhya theory, doership rests only with the Buddhi and not the soul. This is opposed by Vedanta theorists who point out that Buddhi belongs to the inanimate category. The soul, in association with the body, brings about the possibility of action and also the enjoyment thereof. But the soul remains unaffected, though it becomes both the agent and enjoyer owing to association with the body. The famous verse in Katopanishad compares the senses to horses; the objects of enjoyment to the paths they range over, while the Self associated with the body comprising the senses and the mind is shown to be the enjoyer.
