Note 2 at Lu 18:2: This parable of the unjust judge is teaching the same lesson as the parable of the persistent friend recorded in Lu 11:5-8 (see note 3 at Lu 11:5). This is not an exact comparison of God to this unjust judge, teaching us that we should badger God until we weary Him (Lu 18:5) and He grants us our requests. Rather, Jesus was contrasting His willingness to answer our prayers with this unjust judge's unwillingness. The parable is a contrast, not a representation.

God is not only a just judge who will avenge His own elect speedily (Lu 18:8), but we also have Jesus as our advocate (1Jo 2:1), or attorney, who is always making intercession for us (Ro 8:34 and Heb 7:25). However, we have an adversary (the devil) who is constantly accusing us (Re 12:10) and misrepresenting God (the judge). This causes some of us to give up (faint, Lu 18:1) and not even plead our case with God, because we doubt that He would answer us anyway.

Jesus was saying that our Father is not an unjust judge whom we have to pressure into doing what is right. Many times we put more faith in people and their willingness to do what is right than we do in God. Satan has deceived us about the willingness of God to answer our prayers, and Jesus was countering that deception with this parable. Jesus was encouraging us to pray (petition God) and not doubt His willingness to grant our requests.

Most people have interpreted the "he" who was bearing long with them (Lu 18:7) as referring to God, leading them to teach that we just have to pester God sometimes until He gives in to our pressure. That is not good theology. It is much clearer to interpret this verse as saying that God will speedily avenge His elect (Lu 18:8) that petition Him, though he (the unjust judge) didn't.

This widow's actions were commendable. She knew what was rightfully hers, and she refused to take "no" for an answer. If we can be that confident and determined when dealing with unjust people, how much more should we persist, despite the devil's delays, when dealing with our faithful Father?