Whenever a man disputes with one who is more learned than himself to make people know of his learning, they will know that he is ignorant.
If one better than thyself begins to speak,
Although thou mayest know better, contradict him not.
Saadi Shirazi
http://www.poemhunter.com/poem/ch-08-on-rules-for-conduct-in-life-admonition-16/
