'Then Jesus told his disciples a parable to show them that they should always pray and not give up. He said: “In a certain town there was a judge who neither feared God nor cared what people thought. And there was a widow in that town who kept coming to him with the plea, ‘Grant me justice against my adversary.’ “For some time he refused. But finally he said to himself, ‘Even though I don’t fear God or care what people think, yet because this widow keeps bothering me, I will see that she gets justice, so that she won’t eventually come and attack me!’ ” And the Lord said, “Listen to what the unjust judge says. And will not God bring about justice for his chosen ones, who cry out to him day and night? Will he keep putting them off? I tell you, he will see that they get justice, and quickly. However, when the Son of Man comes, will he find faith on the earth?” 'Luke 18:1-8 NIV

This is a parable for teaching the disciples how they should pray if they have difficulty in forgiving another person their sins against them. It is obvious that God will use the Holy Spirit to teach the person praying in their thoughts to forgive another for past sins against them. It is interesting that when Jesus comes back he asks will he still find someone faithful enough on earth to be forgiving the sins of others? Apparently forgiveness is an element of faith and Christ asks if he will find this kind of faith on the earth when he returns? It says that in the last days the love of many will grow cold and this will likely be from unforgiveness. Jesus speaks about his blood which is symbolized by the cup of wine that the disciples shared at the last supper being the Cup of the new Covenant for the forgiveness of sins being poured out for many. The symbolic blood of Jesus Christ in the communion the forgiveness of sins.