By neither hurrying nor slacking off,
we will succeed.

When practicing Chan meditation, we must not be too hurried. But we must also not slack off. If we are too hurried, we run the risk of overdoing it. If we slack off, we will fail to apply enough effort. Cultivating the spiritual path requires holding to the Middle Way. There is a saying,

Hurrying makes things too tight.
Slacking off lets things get too loose.
By not hurrying and not slacking off,
We can succeed at what we do.

If we apply effort in this way everyday and in every moment, without hurrying or slacking off, eventually our skill will generate a response. When this happens, we will achieve an inconceivable state. Those of you who have attained this state should not be overly happy, and those who have not, should not be unduly sad. If a practitioner becomes overly happy, demon of happiness can come and disrupt his samadhi power, causing that person to laugh and smile unnaturally all day long. If somebody asks him what he is laughing about, he will not know.

If he does not even know why he is laughing, then basically he has lost his senses. He has gone mad. A demon of madness has already possessed him. Conversely, if a practitioner becomes excessively sad, worried, or depressed, a demon of sadness can come and disrupt her samadhi power, causing her to sob and cry unnaturally all day long. If someone asks her why she is crying, she may reply, “Beings are suffering so much! They are so pitiful! I wish to cross over all beings.” However, if she cannot even cross over herself, how can she possibly save others? Excessive displays
of sorrow are an indication that a person has been possessed by a demon of sadness.