Parable of the Persistent Widow/Unjust Judge: Luke 18:2-8
Jesus tells the parable of the persistent widow in order to teach about the importance of being persistent in prayer. This parable is also sometimes referred to as the parable of the unjust judge; however, the focus is actually on the widow and her persistence.
The Parable of the Friend in Need is about the same subject as this parable of the persistent widow.
As an introduction to this parable, Luke tells us why Jesus is telling this parable of the persistent widow. "Then Jesus told them a parable about their need to pray always and not to lose heart." (Luke 18:1)
Jesus has also just finished talking about the End Times in Luke 17:20-37, which is why this parable ends with a question regarding Jesus' return, in Luke 18:8, "And yet, when the Son of Man comes, will he find faith on earth?"
Jesus begins this parable by speaking about a judge who is unjust and does not fears God or people. A widow keeps coming to him and saying, "Grant me justice against my opponent." (Luke 18:3)
The judge refuses to grant the widow justice at first, but she keeps bothering him. Finally, the judge decides to grant her justice so that she will leave him alone. It is at this time that Jesus makes his point, "Listen to what the unjust judge says. And will not God grant justice to his chosen ones who cry to him day and night? Will he delay long in helping them? I tell you, he will quickly grant justice to them." (Luke 18:7-8a)
Jesus then says, "And yet when the Son of Man comes, will he find faith on earth?" (Luke 18:8b)
The meaning of this parable is mentioned at the beginning of this passage. Luke says, "Then Jesus told them a parable about their need to pray always and not to lose heart." (Luke 18:1)
Jesus' point is essentially that: If even an unjust judge (who neither fears God nor humans) will grant someone justice because of their persistent, then how much more will God (the most righteous of judges) grant those justice who are persistent in crying out to him.
Jesus then ends this parable by saying "And yet, when the Son of Man comes, will he find faith on earth?" (Luke 18:8)
If we have faith in God that he will grant us justice, then we will persistently cry out to him no matter how long it takes, even if it's months or years, because we believe that God will grant justice.
Jesus asks this rhetorical question, as if wondering if he will find such faith when he returns. The reason this question is rhetorical is because no one can answer it, but we can know that he asked it because he was just discussing his return in Luke 17:20-37.
There are some who believe that asking God to grant justice in a situation more than once means you do not have faith. However, as we can see in this parable, this belief is opposed to what Jesus actually teaches.
Those who have faith will regularly pray to God until he grants them justice, patiently and humbly waiting on God.
On the opposite side, there are those who believe that God will grant them whatever they want if they ask enough times. This belief is also untrue, since there are many prayers that God would never answer. God is not a magical genie, and believing that he is responsible for heeding to our every wish is blasphemous.