What is the essence of cultivating Buddhism, when you get right down to it, it's nothing more than the word "reason."
However, the reason of any school of thought is only a partial truth, not a holistic one.
Yankong too was a Buddha Son well-versed in the sutras, how could he not understand the harms of the five poisons: greed, anger, delusion, arrogance, and doubt.
But the most difficult part about reason is whether you can truly put it into practice.
Because the cost of learning reason is extremely low, the wise predecessors carved their wisdom and reason into stones, recorded them in books, wrote them on paper.
People just look or listen and think they have grasped the reason, but in fact, they haven't even touched the surface.
It's just like those eloquent and articulate folks who talk the talk of lofty and noble reason, but act worse than pigs and dogs.