2 Corinthians 10:3-4

For though we walk in the flesh (as mortal men), we are not carrying on our (spiritual) warfare according to the flesh and using the weapons of man. The weapons of our warfare are not physical (weapons of flesh and blood) Our weapons are divinely powerful for the destruction of the fortresses. 

If we are too earthly minded, carnally minded, fleshly minded we will not overcome in the spiritual realm. Our spirit has been given power and authority to fight all our battles in that realm. We are more than able to defend ourselves by speaking our authority in the name of Jesus. “Our weapons are divinely powerful for the destruction of the fortresses.”