When I look back in history at great generals who risked their troops and their own lives for victory, or at scientists who shut themselves up in their laboratories for months or even years, trying to discover something we now take for granted, or at a missionary who burned his life out by the time he was thirty, trying to get the gospel to some people in a foreign land, I remind myself that this is the mark of greatness. If the desire for comfort is always diverting you, if you can't take pain and you've always got to find the easy way, then you'll never know what greatness is.