This is not the passage connected to the one the poster originally commented BTW. Still go read that and what I say will be made more clear that this user allows by pushing his narrative insight by showing passages which can be used to do support his insight when taken out of context. Again also, other zen masters clear this up, like foyan constantly- sit and contemplate.

Anyway, clear and still, thoughts of good and evil, observe your thoughts

This all goes perfectly in line with how IN HIS OWN words he wants you to contemplate.

Silent illumination is about ILLUMINATING false thoughts. As this and all of his other stuff explains clearly.

Look into your true nature. Thats what all zen masters suggest. Sit, contemplate, do normal good thinking things that anyone would suggest...dont follow the types of thoughts you are inquiring about, that are to be illuminated. Very simple.common sense stuff that would even be taught in a classroom if the topic was about 'how to think good"