What Does It Mean that God's Righteousness is Revealed from Faith to Faith?
Thinking about Romans 1:17.
For in it [the gospel of Christ] the righteousness of God is revealed from faith to faith; as it is written, “The just shall live by faith.” (Romans 1:17)
From faith to faith.
There are quite a few different thoughts on what is meant by “from faith to faith.” Personally, I’m inclined to believe that “from faith” is a reference to the one faith (Ephesians 4:5) or the one system of faith in Christ Jesus - and that “to faith” is a reference to the faith produced in the individual by the gospel system.
The "unto” stresses the aim of the revelation in the gospel. Just as Paul was granted grace and apostleship "unto obedience of faith” (1:5) so the gospel reveals righteousness based on faith “in order to produce” (unto) faith. - McGuiggan, Romans, 67
Paul here means that it is through a system of faith that man’s faith can increase. - Wacaster, Studies in Romans, 31
There are quite a few different ideas about what this phrase means, so my thoughts are by no means “the end of the matter.”
In this context, the kind of faith that brings life is only found in the gospel of Christ Jesus - where God’s righteousness has been revealed.
The just shall live by faith.
The phrase, “the just shall live by faith,” is a quote from Habakkuk 2:4. The prophecy of Habakkuk is about God’s justice upon the nation of Judah and upon the nation of Babylon, which He used to punish Judah for their rebellion against Him.
The ones puffed up with pride were contrasted with those who “lived by faith” (Habakkuk 2:4). The “just” were the ones who set aside pride and submitted themselves to God. The same attitude is required for all who “live by faith” today.
True faith will contain everything that the mind can bring of assent, everything the heart can bring of love, confidence, and trust, and everything that the will can bring of obedience. - Barnhouse, Romans Vol. 1, 208
The righteousness of God is revealed in the gospel of Christ. Do you want to live by faith? Then you must entrust yourself to God and submit to what He has done and what He says.
You cannot “live by faith” apart from the gospel of Christ Jesus. The gospel is God’s power to save - the life promised by God is only found in Christ Jesus.
Just to add another interpretation : Then Paul sets forth his premise, the theme of the epistle, which is: those justified in God’s eyes are those justified by faith (1:16-17). What does this mean in practical terms? It means this: Trust in the LORD with all your heart, and do not lean on your own understanding (Prov. 3:5, ESV). Paul’s theme in Romans is not anything new, for even under the Law (Law of Moses or LM), one was justified by faith; the faith that justifies is an active faith, a faith that trusts in the Lord and obeys His will. The Cambridge Greek Testament Commentary captured the idea in this remark: “to promote obedience (to GOD) springing from or belonging to faith in Him (not from keeping of law)” (E-Sword). Since God’s righteousness is understood when one responds in faith, justification is a matter of understanding from the faithfulness of God to man’s response of faith.