Go with care. Avoid demonic possession.

The meditation topic we investigate is one false thought. Our mind is full of many scattered thoughts. By using the method of fighting poision with poison, we use one false thought to stop all our many false thoughts. Slowly, one by one, we eradicate false thoughts, so they no longer have influence on us. At that time, no matter what state arises, we will not be deluded by it. We will distinguish things clearly and not become possessed by demons. The ancients said, “It would be better to go without enlightenment for a thousand lifetimes, than to be possessed by a demon
for even a single day.”

As we cultivate Chan meditation, we must be cautious and circumspect, and not get carried away. We must be proper, magnanimous, and forthright, so that demons have no chance to trouble us. Idle thoughts open the door to demons, but the meditation topic is the Dharma-treasure that exorcises those demons.