For in it is revealed how G-d makes people righteous in his sight; and from beginning to end it is through trust — as the Tanakh puts it, “But the person who is righteous will live his life by trust.”
HaShem has always been a G-d of mercy and grace. Here Paul alludes to Habbakuk 2:4 which says “Look at the proud: he is inwardly not upright; but the righteous will attain life through trusting faithfulness.” When we out our trust in HaShem, it takes us out of a place of fear and desperation. We know that we have a loving Father he wants to bless us and see us prosper, so why should we worry and fret and lament our lot in life? Living by trust brings believers a mindset of peace and abundance, from there we can see all the blessings in our lives and feel the call to bless others.