All actions are done by Prakṛti (Nature) through its guṇas. One, deluded by egoism, thinks: “I am the doer”.
Krishna had earlier said that none can remain inactive even for a second, for Nature through its guṇas keeps everyone active (3.5). He restates the same truth, in a different note.
By all means, everywhere, all activities are being done by the three qualities (guṇas) of Nature (sattva, rajas and tamas). And man has no option in the matter at all. Sheer ignorance and delusion alone make one feel ‘I am the doer’, with regard to his activities. As the body and its functions are sustained by biological laws and processes, the inner motivations and compulsions are also led by Nature’s subtle spiritual laws. Man is not a doer, but an instrument. Nature alone wields it variously.
Activities, whether inert or sentient, transpire everywhere in Creation. Senses interact with world objects, and mind and intelligence with their objects – all instrumented by Nature. Ignorance alone raises the ego and its claim.