Romans 1:17 :

For in it is revealed God’s righteousness from faith to faith. As it is written, “But the righteous shall live by faith.”

The word “righteousness” simply means to be right, but righteousness can be both our legal position and a way of life. In other words, if you do something wrong and owe a fine for doing it, after you pay it, you have made it right and you have a righteous position. If you never do anything wrong as you live day-by-day, it can be said that you live a righteous life.

I think you could say that this verse is a thesis statement for this theological letter. It very briefly sums up much of what it is about

We will be learning that when we believe in Jesus, our debts are paid in full by Him and we are made righteous by our faith in what He did. At that point we have a position of righteousness. When we live on from that point in our lives as Christians, we have the opportunity to keep having faith in Christ as we live. This gives us the power we need to actually live righteous lives. So, you could say that we go from “faith to faith.” We start our new lives in faith and we walk on from there in faith. This is really the only way that the righteous can truly live. Those who are really living righteously, know that they aren’t doing it on their own. If you try to be truly righteous in the way that God expects, you find out very quickly that you are unable to do it from your own will and power. We must have faith in the One who is righteous in order to be righteous and live righteously.