If you are speaking forth God's Truth and have a Scripture basis for those words, the devil will try to bluff you about it. But if you only have mental knowledge of it, he will succeed in his bluff and you'll give in to it. The words that you speak must be your own revelation knowledge of those words.
God told me: "Believe and confess until you know and possess." When you know and possess the revelation knowledge you have of it: you can talk it, you can walk in it, you can do anything with it.
It's YOURS! It's part of you ... part of your spirit man and part of your soulish man which is in the process of being redeemed, transformed.
This is our Christian walk ... it's a continual thing. You should be progressively growing in revelation. This is our own personal responsibility. Our free will is involved.
God wants us to talk to our own body. Someone else can talk to our body, but the words spoken from our own mouth do have more effect on our body than those of anyone else. This goes for all of us!
Reverend Robert W. & Mary C. Butler