Why a proper understanding of past is important?

The past is ever with us and all that we are and that we have comes from the past. We are its products and we live immersed in it. Not to understand it and feel it as something living within us is not to understand the present. To combine it with the present and extend it to the future ,to break from it where it cannot be so united, to make of all this the pulsating and vibrating material for thought and action - that is life.

Nehru, Discovery of India