The word of God as what has been written in Ephesians 6:10-20 is our full armour. Satan will always try to steal our faith and we do need to be aware of his devices in order to do this. We are mainly snared by the unprofitable words we speak to each other and that is where we leave room for Satan to weaken us as we speak negatively against our brothers and sisters, especially in disagreements.
It is true we are no longer of this world as we have been crucified with Christ and have also risen with Him, Colossians 3:1-4, but yet we still have to live in this world of iniquity and as long as we are still alive Satan will never give up trying to kill, steal and destroy our faith in Christ. It's like Paul's thorn in the flesh as Satan was always trying to buffet him and even prayed three times for Christ to take this away, but look what Jesus told Paul, My grace is sufficient for thee: for my strength is made perfect in weakness. We are still mortal and prone to fall short at times as we are not perfect yet and live in a corruptible fleshly body, but if we continue to walk in the Spirit and keep our focus on Spiritual things from above then no matter what Satan tries to throw at us we will always have the victory over him.
2Co 12:7 And lest I should be exalted above measure through the abundance of the revelations, there was given to me a thorn in the flesh, the messenger of Satan to buffet me, lest I should be exalted above measure.
2Co 12:8 For this thing I besought the Lord thrice, that it might depart from me.
2Co 12:9 And he said unto me, My grace is sufficient for thee: for my strength is made perfect in weakness. Most gladly therefore will I rather glory in my infirmities, that the power of Christ may rest upon me.
2Co 12:10 Therefore I take pleasure in infirmities, in reproaches, in necessities, in persecutions, in distresses for Christ's sake: for when I am weak, then am I strong.
When it comes to Satan we can not fight him on our own, but only by the power of the word of God can he be defeated in our life.