Krishna explains that one needs to do one's duty without a desire or expectation for the result. Adapting the middle path is the way of life of a sanyasi or a karmyogi.
The body and all things are made of 5 elements, that is, earth, water, air, fire and ether, and it is also made up of 3 more elements that cannot be seen, that is, the mind, intelligence and ego.
People worship to gain money, and/or knowledge, or for removal of grief and pain, and to walk on the spiritual path. But, Krishna explains, everything is God.
Krishna further explains that God has no shape or colour, God is without any form and is in everything.
Krishna then shows to Arjun his great form. Arjun sees people being born from and dying into this form.