When the devil comes against the believer with his sickness, disease, poverty.... anything contrary to the attributes of God, he is treading on God's property. That's illegal! He's an outlaw! He's not allowed to do that! EXCEPT when WE allow him to.
The key is: when we allow him to take the authority to do these things to us. How do we do that? By our words. God says to Speak Life, Don't Speak Death! Both Life & death lie in the power of our tongue.
When the devil comes at me saying: "I am going to kill you", I tell him: "You cannot kill me.... I'm a Blood-bought child of the Living God! God owns me lock, stock, and barrel. You're treading on God's property and His Word says that I'm walking in Health, Healing, Prosperity, and all the attributes that He has for me. I am walking in them. You do not have the right to tell me that I can't and won't because God has ALREADY GIVEN them to me!"
Reverend Robert W. & Mary C. Butler