No matter how sound the teaching is if you don’t believe you would not receive it. The same goes for authority.

You can preach the gospel to a person if he chooses not to believe he would not be saved,

In the same way, you can tell a person of the authority he has in Christ if he also chooses not to believe he would not operate in it.

If we say all you have received because of salvation and you refuse to believe it, you would not function in it.

What if all the issues you had about the devil are all in your head and you are more powerful than you think.

If only you dare believe. It’s up to you to believe who you are as said in the scriptures.