“Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness…” Ephesians 6:14.
There cannot be gospel without truth coming first. People have to know and feel that they are sinful before they can hear and accept the good news of salvation. We also must speak truth and it is the foundation of the kingdom of God. Satan is the father of lies and God is the opposite. Everything that God says is perfect truth and Satan is a perfect liar. Well, maybe not that perfect… So, take truth as a weapon against the devil and smite him with it.
Righteousness is the weapon that protects your heart. You are redeemed by the blood of the Lamb and He has become your righteousness. You cannot be condemned for your sins as they are forgiven and washed away. Your righteousness does not depend on your works, but on Jesus work on the cross of Calvary. You have to believe as it is the only way for that breastplate to hold and protect your heart from the fiery arrows of the enemy.