What was the idea that rulers get their power from god

It is called 'theocracy' (from the Greek word 'ΘΕΟΚΡΑΤΙΑ') which means that the ruler's power derives from God or a deity (depending on the historical time  which is referred). Therefore, the ruler has all the powers and cannot be challenged by any living creature on earth except for God, who will be the final judge of his actions.

answer; taking detailed notes during the interview;

answer; participant observation method;