Sit down before fact as a little child, be prepared to give up every preconceived notion, follow humbly wherever and to whatever abysses nature leads, or you shall learn nothing.  

You will never be able to escape from your heart. So it's better to listen to what it has to say. That way, you'll never have to fear an unanticipated blow.

释义：不考虑在安逸的环境中要想到危难，用节俭来戒除奢侈，不使自己的道德处于深厚的境界，不能使自己的情欲战胜物质欲望，这就像砍伐树木的根却想要树木长得茂盛，堵塞水的源头却想要水流得长远一样荒谬。