I’ve always been big on boundaries.
Boundaries are the set of rules which determine whom and which things will be allowed to affect you. Boundaries require conviction, discretion, and tact, as they are most often applied to situations where people ask you to do or be a part of something that is ultimately going to have a net-negative effect on your life.
Rejection is the stated and enforced decision which keeps harm, evil, or malevolent individuals out of your space. Discernment, moral conviction and a willingness to offend in order to keep those convictions are required.
Non-Acceptance is a different animal though. Where the first two deal with concrete outside circumstances trying to impose on your life, non-acceptance is the simple rejection of non-truth. Be it worry, false accusations, demonic oppression, blame, or guilt imposed by others, non-acceptance is key to walking through the muck of life and not letting it stick to you.
The delivery does not require emotion, conviction or tact, it is a simple statement where the rejection of non-truth is a matter of fact, like a business policy that states, “We don’t do that here. If that’s the way you want to be, take your business elsewhere.”