"But that no one is justified by the law in the sight of God is evident, for “the just shall live by faith.” Galatians 3:11
The just shall live by faith. We could also say it that this way. The just, those whom Jesus has forgiven and gave His life for, and who have received Him as Lord by faith and been born again by His Spirit, they are the just. And being found now in Christ redeemed by His blood we have been freely justified by faith in Him. So now we have within us the ability to live by faith. The unbeliever walks by faith also, but not faith in God. He walks by the dictates of his flesh, the world, and the devil.
But as the children of God, we have been given a special privilege and a source of life-giving understanding that we are the children of God. As His children we have family privilege that is not given to others except they seek it and receive it through faith in Jesus Christ.
Because of what Jesus has done for us we now share in the fulness of His presence, His power, His provision, and His knowledge, wisdom and understanding in all things. So, it is our right, our privilege, and our responsibility to walk in the world by faith in God alone. Without faith it is impossible to please Him. Nothing else gets us there, only faith working by love.