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.
If you see your nature, you don't need to read sutras or invoke buddhas. Erudition and knowledge are not only useless but also cloud your awareness. Doctrines are only for pointing to the mind. Once you see your mind, why pay attention to doctrines?
The Buddha is your real body, your original mind. This mind has no form or characteristics, no cause or effect, no tendons or bones. It's like space. You can't hold it. It's not the mind of materialists or nihilists. If you don't see your own miraculously aware nature, you'll never find a Buddha, even if you break your body into atoms.
To have a body is to suffer. Does anyone with a body know peace? Those who understand this detach themselves from all that exists and stop imagining or seeking anything. The sutras say, "To seek is to suffer. To seek nothing is bliss." When you seek nothing, you're on the Path.
If you use your mind to study reality, you won't understand either your mind or reality. If you study reality without using your mind, you'll understand both.
When your mind doesn't stir inside, the world doesn't arise outside. When the world and the mind are both transparent, this is true vision. And such understanding is true understanding.
The true Way is sublime. It can't be expressed in language. Of what use are scriptures? But someone who sees his own nature finds the Way, even if he can't read a word.