The helment of Salvation protects the head of the believer. Think about the fact that it is our in our minds that the attacks of the devil happen. Spiritual warfare is not a physical battle. It is a spiritual fight. When Satan attacks, he attacks us in the mind. One of his most powerful weapons is to attack with discouragement and doubt. He knows that if he causes a believer to doubt or to be discouraged that he can negatively impact our spiritual impact in the world and in our personal spiritual walk with the Lord. Remember, God wants His children to depend on Him. He wants us to willingly trust Him.