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.
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.
All Buddhas preach emptiness. Why? Because they wish to crush the concrete ideas of the students. If a student even clings to an idea of emptiness, he betrays all Buddhas.
To see nothing is to perceive the Way, and to understand nothing is to know the Dharma, because seeing is neither seeing nor not seeing, and because understanding is neither understanding nor not understanding.
Still others commit all sorts of evil deeds, claiming karma doesn't exist. They erroneously maintain that since everything is empty, committing evil isn't wrong. Such persons fall into a hell of endless darkness with no hope of release. Those who are wise hold no such conception.
Unless you see your nature, you shouldn't go around criticizing the goodness of others. There's no advantage in deceiving yourself. Good and bad are distinct. Cause and effect are clear. But fools don't believe and fall straight into a hell of endless darkness without even knowing it. What keeps them from believing is the heaviness of their karma. They're like blind people who don't believe there's such a thing as light. Even if you explain it to them, they still don't believe, because they're blind. How can they possibly distinguish light?