In Romans 1:16-17, Paul says the following:

For I am not ashamed of the gospel, for it is the power of God unto salvation to everyone who is faithful, to the Jew first and also to the Greek; for the righteousness of God is revealed in it from faith(fulness) unto faith(fulness) (ἐκ πίστεως εἰς πίστιν), just as it is written, “but the righteous one will live from faith(fulness).”

I said yesterday that v. 16 is a pastoral statement of confidence in the gospel to a dispirited community.  The return of the Christian community’s former leaders and the renewed emphasis on Law-observance have produced tension and division.  There is a loss of confidence in the gospel, which is the reality of God’s mission to reclaim creation and unite humanity in Christ by the Spirit.  The reality and the radical implications of God’s new move have left many in the church unsettled.  Paul expresses confidence, however, that God is indeed unleashing his saving power through this new move in Christ rather than through Israel.

I think that this explains Paul’s enigmatic statement in v. 17b, ἐκ πίστεως εἰς πίστιν, and his quotation of Habakkuk 2:4.

As far as interpreting ἐκ πίστεως εἰς πίστιν (from faith[fulness] unto faith[fulness]), there is nothing in the text of Romans that drives interpreters in any singular direction.  Is this God’s faithfulness that elicits believers’ faith?  Is it believers’ faith that grows, one step of faith at a time?  Any interpretation fits here, frankly.

I think it has to do with the outworking of God’s saving power that is at work among God’s faithful people, whatever form that human response of faithfulness will take and whatever God requires.  This may make sense once we consider the Habakkuk quote.

Hab. 2:4 is paradigmatic for Paul’s ministry.  It emphasizes God’s approved response to his word.  God’s approved person responds to God’s word with faithfulness, fidelity, and loyalty, however surprising the revelation or contrary to human expectations. 

In Habakkuk 1, the prophet cries out to God because of the wickedness of Judah.  God answers Habakkuk by revealing his plans to judge his people by calling upon a nation more wicked than Judah, the Babylonians.  Habakkuk complains about this to God, asking how God can do this.  How can this be?  You are too pure to approve of evil!  This isn’t like you at all!

As Habakkuk 2 opens, the prophet readies himself to receive the answer.  God confirms that he will also judge the Chaldeans for their wickedness, but his intentions to use this pagan nation to judge Judah are set.  And God’s approved person will not respond with proud resistance (v. 4a), but with fidelity, faithfulness, loyalty to God no matter how upsetting or disturbing the word of the Lord is (v. 4b).  Hab. 2:4 emphasizes God’s approved response to his word that flies in the face of expectations and established assumptions of how God must act. 

This passage is paradigmatic for Paul because it highlights the required posture of nimble readiness to do whatever God asks of his people.  They must be willing to adjust previously well-established patterns of behavior and thought in the light of a new word from God.

God’s ways, while surprising, are always completely consistent with God’s self-revelation.  It’s just that it’s so easy to assume that God shares our prejudices and assumptions—those conceptions that grow unnoticed and creep into our thoughts about God.

The problem is not that God’s ways are always radically changing.  It’s that we don’t know God and his ways as well as we think we do.

Paul envisions his ministry and the problems in Rome through the lens of Hab. 2:4.  The Roman church is struggling with the form of Christian faithfulness.  What shape does it take?  What does a community created and sustained by the God of Israel look like?  The church is struggling to embody Christian faithfulness whereby Jews and gentiles participate in community together.  Paul quotes Hab. 2:4 in order to emphasize that something radically new is going on in light of the death and resurrection of Jesus Christ and the sending of the Spirit.  God is forming multi-ethnic communities of Jesus-followers in which Jew and gentile embrace one another as siblings in God’s new family. 

It’s hard for us to grasp how upsetting this was for the early church.  In the experience of the first Christian generation, faithfulness to the God of Israel could only be rendered within Judaism.  The revelation of the gospel, however, is that God is now saving people without regard to their ethnicity.  Just as in Habakkuk’s day, this is something radically new—even though it is in complete continuity with God’s acting all along.

Just as with Habakkuk, this radical move of God calls for that nimble readiness to make adjustments out of loyalty and fidelity to the God of Israel.  God is doing something that challenges the assumptions and developed prejudices of how God must act, and he is calling for a Jesus-oriented faithfulness in which fidelity to the God of Israel outstrips all other loyalties and commitments.