When all is lost and all is dreary, When fate is gone and you must go on, When you go on without a light, When you fight through the worst of night, Du bist der übermensch. When you beat the hopelessness and decay, Du bist der übermensch. When you fight a world meaningless, Du bist der übermensch. When you create meaning from naught, Du bist der übermensch
The poem is based on Nietzsche's idea of "the übermensch", literally the "over-man" or "above-man", thus the repeated phrase means "You are the over-man", but "übermensch" can't really be translated. It's the idea of the person who finds his own meaning in a godless world. Nietzsche belived that the Enlightenment "killed", or rather disproved, God, making there be no objective morality and meaning.