reference to the context: These lines are taken from the poem 'Where the mind is without fear'.This poem is beautifully woven by Rabindranath Tagore. The whole poem is in the form of a prayer. The poet prays to the Almighty for the all-round progress and prosperity of his country. EXPLANATION: In these lines the poet presents a contrast between reason and dead habits with the help of 2 delightful metaphors.In the first phrase reason or rational thought is like the clear stream, pure and ever flowing. On the other hand dead habit or orrational belief is as dull and monotonous as the endless sands of a desert where everything is static as against the dynamism of the waters of a stream.The poet prays that his countrymen should be guided by reason which would rid them of the old habits and customs which are no longer useful and thus lead them on to the path of progress and prosperity.