We usually think of our mind as just thoughts and emotions, but according to the teachings of Buddha, these make up only one aspect of the mind. The teachings tell us that the mind has two aspects: the appearance of mind, and, more important, the essence or nature of mind. The appearances of mind are like the rays of light streaming from the sun, while the very nature of mind is like the sun itself in all its glory.
The teachings tell us, rather than trying to understand each thought and emotion that arises in our mind, instead we should try to understand the nature of mind itself. When we understand the nature of mind, it is one-medicine for all ills. By knowing one thing we come to know all.