You cannot fight the devil in the physical because he is a Spirit, you must create a Spirit or Spirits against him by your tongue.
If there is need to fight the devil with fire your tongue will create it, or if you want to use other weapons like Sword, Arrow, Hammer, and Brimstone against him, and your tongue will create them as you are praying. Though you may not see all the weapons and Spirits created by your tongue while praying, but I tell you the truth, they come alive as you pray with faith. You can only see the spiritual through the eyes of faith, you just need to believe and it will come to pass.
We create physical things with our hands and spiritual things with our tongue.
If you say to the blind receive your sight, it will be so if you doubt not. You can also tell the lame to arise and walk and he will do so if you doubt not.