Four types of people

We meet four types of people in life, 
And we must know how to deal with them: 

Those who know and know that they know - they are the wise - follow them. 
Those who know but don't know that they know- they are misguided - enlighten them. 
Those who don't know and know they don't know- they are the students - guide them. 
Those who don't know and don't know they don't know - they are fools - avoid them.

~ An Arabian proverb

Teaching

Central Asian monk teaching East Asian monk. 9th century fresco from the Bezeklik Thousand Buddha Caves near Turfan, Xinjiang, China.