brace oneself和bear oneself

brace oneself和bear oneself
Let us therefore brace ourselves to our duties,so bearing ourselves that,if the British Empire and its Commonwealth last for a thousand years,men will still say,"This was their finest hour."
查了字典,只有brace oneself for,是未雨绸缪之意,那么这里介词to怎么理解呢?
还有bearing ourselves