What does the Bible say about the just living by faith?

The phrase 'the just shall live by faith' appears four times in Scripture, indicating its critical importance to the Christian life. It encapsulates the doctrine that those whom God has justified—those who are righteous in His sight—derive their spiritual life from faith in Him. This faith is not a mere acknowledgment of God's existence but a deep trust in His character and His promises, as seen in Hebrews 11:1, which describes faith as 'the substance of things hoped for, the evidence of things not seen.'