neither gods nor demons get it

ਜਾ ਕੀ ਧੂਰਿ ਕਰੇ ਪੁਨੀਤਾ ॥ 

The dust of His feet purifies.
ਹੇ ਭਾਈ! ਜਿਸ (ਪ੍ਰਭੂ) ਦੀ ਚਰਨ-ਧੂੜ ਪਵਿੱਤਰ ਕਰ ਦੇਂਦੀ ਹੈ,

ਸੁਰਿ ਨਰ ਦੇਵ ਨ ਪਾਵਹਿ ਮੀਤਾ ॥ 

Even the angelic beings and gods cannot obtain it, O friend.
ਹੇ ਮਿੱਤਰ! ਉਸ ਨੂੰ ਦੇਵਤੇ ਮਨੁੱਖ ਪ੍ਰਾਪਤ ਨਹੀਂ ਕਰ ਸਕਦੇ ।

[This is just one exegesis of this shabad. In this case, I take angles/gods/demons to be symbolic of various states of mind, but they can be taken literally. That is an important meaning as well.]

Those who consider themselves fully or trully evil or good can never get the dust of the Lord because it requires a mortal, fallible person who is also cognizant of their fallibility to learn (i.e., humility). Someone who has already categorized themselves so rigidly does not have the flexibility to accept truth or to place their trust in something greater. You have to put down the illusion.

See related: you have to see it for yourself, you only have a relationship with a person you spend time with.