Whoever realizes that the six senses aren't real, that the five aggregates are fictions, that no such things can be located anywhere in the body, understands the language of Buddhas.
To enter by reason means to realize the essence through instruction and to believe that all living things share the same true nature, which isn't apparent because it's shrouded by sensation and delusion.
Leaving behind the false, return to the true: make no discriminations between self and others. In contemplation, one's mind should be stable and unmoving, like a wall.
The mind's capacity is limitless, and its manifestations are inexhaustible. Seeing forms with your eyes, hearing sounds with your ears, smelling odors with your nose, tasting flavors with your tongue, every movement or state is all your mind.