Pray always and do not lose heart is the message Jesus gives his disciples today (Luke 18:1-8). He illustrates it with the parable of a widow and an unjust judge. The widow is persistent and the judge finally grants her request: Because this widow keeps bothering me, I will grant her justice, so that she may not wear me out by continually coming.
Here are some thoughts on persistent prayer from Pope Emeritus Benedict, given during a homily on the Feast of the Epiphany, January 6, 2012:
The restless heart, … echoing Saint Augustine, is the heart that is ultimately satisfied with nothing less than God, and in this way becomes a loving heart. Our heart is restless for God and remains so, even if every effort is made today, by means of most effective anaesthetizing methods, to deliver people from this unrest. But not only are we restless for God: God’s heart is restless for us. God is waiting for us. He is looking for us. He knows no rest either, until he finds us. God’s heart is restless, and that is why he set out on the path towards us – to Bethlehem, to Calvary, from Jerusalem to Galilee and on to the very ends of the earth. God is restless for us, he looks out for people willing to “catch” his unrest, his passion for us, people who carry within them the searching of their own hearts and at the same time open themselves to be touched by God’s search for us.... [L]et yourselves be touched by God’s unrest, so that God’s longing for man may be fulfilled.