Isaiah 54:17 says. But no weapon that is formed against you shall prosper, and every tongue that shall rise against you in judgment you shall show to be in the wrong. This [peace, righteousness, security, triumph over opposition] is the heritage of the servants of the Lord [those in whom the ideal Servant of the Lord is reproduced]; this is the righteousness or the vindication which they obtain from Me [this is that which I impart to them as their justification], says the Lord.
The Bible does not say that there will not be any weapon formed against us. It does assure us that the weapon formed against us will not prosper. No weapon formed against me shall prosper it says. Prosper meaning, “succeed at reaching its intended purpose.” What a promise from God!
The Bible says that the devil comes to steal, kill and to destroy. (John 10:10) The purpose of the weapons that are formed against is to discourage us to the point of giving up. And while he continues to try and bring death and destruction to your life and to mine, he has no power to succeed.
The reason the Son of God was made manifest (visible) was to undo (destroy, loosen, and dissolve) the works the devil [has done]. (1John3:8)
Between you and the weapon (of the enemy), there is the Lord God Almighty. God is all around you. God goes for battle every time the enemy shows up, and He looks at your enemy as His own. An attack against you is an attack against the Lord God Almighty.
Be encouraged and know that God is for you regardless who or what might be against you.