When we hold blame and resentment toward the world, it is an indication of an ego living in perceived separation from the true Self.
If that blame and resentment is left unresolved—if one does not see through it and beyond it, receiving the lesson from what we experienced, and moving on—the ego can’t help but project that blame and resentment onto someone or something in the apparent world beyond the body. The ego will, without fail, make such a projection.
What then results is we look upon the object of our blame and resentment and consciously or unconsciously (usually the later) our inner state of separation is projected into our relationship with this object… be it a person, thing, or situation (which will involve people and/or things).
If such projection is left unchecked and is allowed to play out over time—another creation of the ego mind—the consequence is we will experience separation from the person onto whom we are projecting. Simply put, if we harbour blame and resentment toward a person it will result in the development of perceived separation from that person.
This projected separation will take on a life of its own. A life fed by our own inner state of separation and conflict. The outer will reflect the inner. Greater resentment will more than likely build up, and the ego will find an ever increasing number of ways to justify feeling separate from the person onto whom we are projecting. This is an attack by the ego upon the perceived other. It is a form of warfare, reflective of the conflict within the person who believes the lie of separation upheld by their persona / ego.