if you have the courage to handle your life,then you can handle others' lives.
楼主的翻译应该是这样才对：
A man who has the courage to grasp his own life,can grasp others' life as well.为什么要改动，哪里的问题？因为这不是因果关系。是因果关系啊肯定不是因果关系啦，难道因为你有勇气把握自己的生命，所以你可以把握他人的生命吗？楼主想翻译的这句话应该是条件句来的