When translating the pivotal verse of Romans 1:17, we come across the Greek preposition "ek", which mostly means "from out of", suggesting a movement from an interior position outward. So verse 17 could read like this, "For the righteousness of God is revealed in [the gospel] *from out of* faith into faith. Moreover, as it has been written, the righteous one will live *from out of* faith." This translation of 'ek' makes sense when we understand that the word for faith also can mean "faithfulness".
I am inclined to think, then, that the apostle Paul is referring to both the faithfulness of God and
especially the faithfulness of Christ in fulfilling His covenant with (a) His people and (b) with all of mankind [think, Abrahamic Covenant in Genesis 12:1-3]. The book of Romans, as with all of
Paul's writings, then, would primarily be concerned with revealing how faithful God is from before the foundation of the earth in bringing about a solution to man's problems; his selfishness and