The basics teachings of Buddha are about understanding what we are, who we are, why we are. When we begin to realize what we are, who we are, why we are, then we begin to realize what we are not, who we are not, why we are not. We begin to realize that we don't have basic, substantial, solid, fundamental ground that we can exert anymore. We begin to realize that our ideas of security and our concept of freedom have been purely phantom experiences.
From "The Practicing Lineage," in The Mishap Lineage: Transforming Confusion into Wisdom.