Caste duties according to the Bhagavad Gita

The Bhagavad Gita contrats the ideas of Zarathustra and Confucious in the aspect of self control. Zarathustra and Confucious thought that a man has the ability to better himself and make changes to his life. The Bhagavad Gita basically states that one can not change his destiny and his future self is already set in stone. These groups all had the same thoughts about people doing good, itbis just that the Bhagavad Gita says that one has to do good, and Confucious and Zarathustra say to do good for a purpose.