During the Kurukshetra war, when a confused Arjuna turned to his charioteer, Lord Krishna for advice, Krishna stated, in the form of the Bhagavad Gita, some rational philosophical concepts which remain relevant today.
In this quote, Krishna focuses on two main choices in life – whether to accept pre-existing conditions, or to take up the onus of changing what needs to be changed. His wisdom was evident throughout the course of the war, in which he helped the Pandavas win.