It is not given to the cleverest and the most calculating of mortals to know with certainty what is their interest. Yet it is given to quite a lot of simple folk to know everyday what is their duty  -   Winston Churchill     Quotes
It is not given to the cleverest and the most calculating of mortals to know with certainty what is their interest. Yet it is given to quite a lot of simple folk to know everyday what is their duty Winston Churchill