Since books are compared to medicines, there are naturally two kinds of medicines: good medicine for fools, fake medicine and harmful poison. Even if it is a "good medicine", we should pay attention to taking it in a timely and appropriate amount, otherwise it will be a bad thing.
Brothers live in harmony, and friends are honest with each other. -Chen Ziang's motto
Pinyin is not xing dün hémé, pé ng y ǐ u d ché ng x n.
Explain that brothers should be harmonious and friends should be honest.
It means that brothers should respect harmony and friends should pay attention to honesty.