I am not sure that there is one particular passage that is more representative of the religion than others. In my mind, the Hindu religion is based off of all that is written in the Gita. I am not sure there is one particular passage that can exemplify the religion. The more appropriate task would be to identify any element of the text and connect that to the Hindu faith. For example, take a quote Arjuna says at the very beginning of the text:
Now I am confused about my duty and have lost all composure because of miserly weakness. In this condition I am asking You to tell me for certain what is best for me. Now I am Your disciple, and a soul surrendered unto You. Please instruct me.
The very basic element of how the Hindu faith is constructed lies in this moment. The moment in which the human is faced with insurmountable agony, conditions that defy the very condition of happiness in mortality, it is at these moments where the human submits to the will of the divine. Hinduism stresses much in a way that the human being is able to surrender their own sense of self in these moments, submitting to a larger configuration or design that makes the pain of the temporal something to be understood and a fraction of it grasped in the act of submission. Another example of a passage that represents much of Hindu thought can come from Krishna himself:
It is said that there is an imperishable banyan tree that has its roots upward and its branches down and whose leaves are the Vedic hymns. One who knows this tree is the knower of the Vedas.
The connectedness of the elevated human being is described here. The image of the tree is a significant one in the religion, as there is a continuity between all life. Human, animal, and plant are all life forms in which the supreme Brahman is evident, and the recognition of this interconnected nature of being is where a human understands the power of both the religion's discourse and the individual's place within it. Continuing on this idea of how each portion of the tree has relevance furthers this idea that the supreme being is in everything, being everywhere and nowhere at the same time. The reference to the "Vedic hymns" being the leaves brings this out. This passage is another example as to how anything in the text can be linked to the Hindu religion and its thought.