Henry talks about the heartwood sutra, an early teaching from the pali cannon that uses a tree as its metaphor for the journey of practice. A tree has numerous layers of bark (each layer is a level of practice), the deepest layer or the core layer is the Heartwood which is total universal freedom.
Next, he returns to the wash your bowls koan from the Gateless Gate and Mumon’s commentary. Henry explores the unknowable zen journey which pulls us into and through a vortex of not knowing. Trust the practice and drop all opinions about how the practice should be. The journey is unknown.