What is the armor of God other than armor given to us by God himself? Truth, righteousness, preparation by the Gospel of peace, faith, salvation, and the word of God are all given to us by God himself to protect us from the powers of darkness, against authorities and principalities and against Satan himself. All of these things have been bestowed upon all those who believe from God. It is His truth, His righteousness, His training, His faith, His salvation, and His word.
If any of it were ours it would be as good as worthless to us. Can armor made by man protect his soul? Can a shield protect against temptation or can a helmet protect against the fires of Hell? No, but God has bestowed upon us all these things through Christ Jesus. No longer when he looks upon us does he see our sins, but rather he sees Jesus Christ crucified as our armor. God himself is the armor which protects us and surrounds us. In a certain sense Jesus Christ lives within us, but we also live in Him. It's the divine mystery that unites us to Christ but it's the only way we are going to make it out of this mess alive.