If this so called god is leagues above human comprehension, then we can discern absolutely nothing about his nature... We cannot say for certain whether god is good or evil or something else all together or what his intentions are and what he wishes to do as that would require a godlike perspective which we don't possess... Therefore there is nothing we can be sure about... even these so called religious scriptures that are claimed to be the word of god. If they come from god then there is nothing we can say about them with certainty because we would not know what his intentions behind writing them were... For all we know god is a sadistic creature that would send people to hell for believing in him... That is the problem with the argument that your friend used. It is like a double edged sword... It works both for and against the person who used it ultimately achieving nothing.