Negative Airs
Master JiGong said,
"If one does not take in the negative airs or energy
It will leave by itself
The negative airs are unhealthy activities, evil, abnormal, off-centered, irregular…etc
Things such as audio and visual pleasures, goods and gain, supernatural skill
Obscene and immoral expertise or any external objects that can damage
The spiritual energy and harm the mind and nature are all termed as negative airs
If you don’t pay attention to them
The negative airs will subside and withdraw themselves
There is no way they can attack and harm you
If there is a ‘silky thread’ (trace) of thought to invite them
Then the perfectly clear and calm Self-Nature would be damaged
It would lose its clarity and whiteness (purity) immediately
Then, even if you have a great and sound aspiration
And a broad way before you
It will all be shaded by the negative airs
What a waste!
All TAO cultivators must NOT be unaware of this
And must be attentive to this" 
Master JiGong further said,
"The mind is the key to stableness of the mind
And stableness is the ladder to become a Buddha
The mind’s power is ever-flowing and does not stand still at one place
Hence, the comprehension of things and affairs
At each individual moment is different
When the state of mind has elevated to a certain point
Then one can reach a certain Heavenly-Stableness
This is the ladder to attain perfect universal awareness"
Once I heard a parable
A vegetarian monk who had attained great awareness and stableness
Decided to descend from the mountain to spread the Truth
Upon reaching a village he passed by a stall selling pork bun
As he was passing by, he could smell the steamed pork bun
His mind told him ‘Ah! Smell good’
Immediately his leg had nine red patches of swollen wounds
The swollen wounds appeared like nine different human heads
He then went into deep meditation to find out why
He discovered that the nine heads were his previous lives spiritual creditors
Because of the ‘silky thread’ of thought of the pork bun
His purity and whiteness were attacked by his spiritual creditors
His creditors were waiting for the opportunity to harm him
With this parable 
TAO cultivators are made aware of this and pay attention to the negative airs
Even in the darkest corner.