Srimad Bhagavat Gita commentary chapter 18 chapter 15-16

 Chapter 18 verse 15-16               

“These five are the contributory factors for whatever action is performed, whether proper or improper, with body, speech, or mind. Those who do not understand this regard the soul as the only doer. With their impure intellects they cannot see things as they are.” 

Without coming together of body, soul, senses, effort and Divine Grace, nothing can be done. Without this knowledge, we think we do things- this is called doer ship and Bhagwan has earlier in Bhagavat Gita asked us to drop the doer ship. He says if we didn’t understand this concept, we would regard the soul as the doer. I would say we would regard different instruments as the doer based on our spiritual maturity. Newer souls would think the body and senses are performing the action, passionate men would think that their effort is delivering the action; evolved spiritual seekers recognize the soul different from body, senses and mind but still might think they are the doers. Only the enlightened beings and those who have surrendered their will to Divine realize the presence of GRACE in the scheme of things.