Apostle Paul writes in Ephesians 6:12 “ For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of the dark world and against the spiritual forces of evil in the heavenly realms.”
Our enemy is Satan and the fallen angels.
I believe, in order to fight with him effectively, it is important that, we must know who he is, how strong he is, how he works and what kinds of weapons he uses.
It is also important for us to know what are the weapons, which God has given to us to stand against him and his demons.