The just shall live by faith, but you must know that you are justified to approach God for grace confidently. When you believe you are justified, you'll live by faith. When you live by faith, you'll access grace. When you access to grace, you will live by his spirit and obey him from the heart. You must be convinced that you are justified through the blood of Christ so you will remain confident before God and not disqualify yourself from receiving from him.
Ephesians 3:12 in whom we have boldness and access with confidence through our faith in him.
Our faith is not in our faith, it’s in him. Living by faith is not living by the strength of my ability to believe. Living by faith is living persuaded of all that Jesus has accomplished on my behalf. If I am facing something in life that Jesus affected on the cross, I have the right to believe that what Jesus paid for should be the reality in my life rather than the temporary circumstance I may be facing.