Paul gives us another reason why he is not ashamed of the Gospel of God - that in it God’s righteousness is revealed.
We look at objective righteousness (the righteousness of Christ, imputed to us by faith) and subjective righteousness (that which God works in us as He makes us more and more like Christ here on earth). We see that all of these are worked in us through faith.
We are challenged as to whether we have the faith through which this righteousness comes to us. Without it, we are lost, but if we have it, we have eternal life, as we read in the quote Paul gives from Habbakuk: ‘The just shall '’live’‘ by faith’.