A boundary is a change to my own behavior. It does not require anyone else to change, and it does not matter how anyone else reacts.
A boundary is something I refuse to do. A boundary is not something I tell you not to do.
So for instance, here’s a boundary from prison ministry: I do not accept gifts from prisoners.
Here is a statement that is not a boundary: “You cannot give me a gift.”
Now I may very well say that, and I have the right to say it. In fact if an incarcerated person does not realize they aren’t allowed to give gifts then I should say it. But it’s not a boundary.
Here’s a more subtle example. Let’s say I have a friend who drives me nuts when he drinks because alcohol turns him into a lunatic. This is a boundary: “I don’t hang out with you when you drink.” That’s something I do. His response doesn’t matter and he is not required to change.
This is not a boundary: “I won’t hang out with you if you drink.” Why is the word “if” in there? That suggests he needs to change. No. He does not need to change. I need to change. That’s what setting boundaries means. Setting boundaries means MY behavior is going to change.
Here is an even worse example of a non-boundary: “If you drink, I’m gonna (insert promise, emotional outburst or outright threat here.)” Now I’m just venting. Here’s another terrible example of a non-boundary: “Dude, you need to deal with your drinking.” Now I’m just being controlling.
So there you go. Remember, if you are trying to get someone else to change their behavior, then you are not setting a boundary.