That being so, due to impure and unrefined intelligence, he who views the pure impersonal Self as the doer, verily does not see at all. He is of perverted vision (mind).
Krishna points to the impersonal, non-acting Self, the inmost core of our personality, as he had explained right at the outset, while responding to Arjuna’s request to enlighten him (2.12). Then it was to show that everyone is immortal, undying.
Here the emphasis is on ‘non-acting-ness’, because Arjuna is bothered by the cruel war he is out to fight. Krishna says action and fruition are there, but not at the inmost level of the performer. One’s body is visible, gross, consisting of matter and energy. But this entire structure changes inside the body, when you reach the plane of mind, intelligence and further. It is beyond the ken of matter and energy.
How can then action done in the physical level involve the unphysical, spiritual level of one’s being? To think it can, is but the result of ignorance, even perversion – a denial of the Self!