Fear of death is not wisdom, since no one knows whether death may not be the greater good.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“He has been a soldier, and has remained at his post, as he was ordered to do. Now “God orders me to fulfil the philosopher’s mission of searching into myself and other men,” and it would be as shameful to desert his post now as in time of battle. Fear of death is not wisdom, since no one knows whether death may not be the greater good. If he were offered his life on condition of ceasing to speculate as he has done hitherto, he would reply: “Men of Athens, I honour and love you; but I shall obey God rather than you,* and while I have life and strength I shall never cease from the practice and teaching of philosophy, exhorting any one whom I meet....” source