过去是知识的源泉，未来是希望的源泉。热爱过去意味着对未来的信心。

做事情，不能有伤害别人的坏念头；但要有警惕他人、防备他人的念头。这是在告诫与人交往思考不周的人。

The only limit to our realization of tomorrow will be our doubts of today.

True freedom is not about doing what you want, but about not doing what you don't want to do.

【释义】如果一个人不能做到孝敬父母，他也无法树立忠诚的品质。