The judge grants the widow justice because of her persistence; he is unwilling to look bad in public. How much more will god grant justice to God's chosen ones, meaning those who pray and work for justice on behalf of others.
This parable of Jesus ought give us pause about our prayer lives. While God wants the things that are best for us, perhaps justice, peace, and care for one another are at the top of the list. Are these the things for which we pray?