Luke 18:1-8 Then He spoke a parable to them, that men always ought to pray and not lose heart, saying: "There was in a certain city a judge who did not fear God nor regard man. Now there was a widow in that city; and she came to him, saying, 'Get justice for me from my adversary.' And he would not for a while; but afterward he said within himself, 'Though I do not fear God nor regard man, yet because this widow troubles me I will avenge her, lest by her continual coming she weary me.'" Then the Lord said, "Hear what the unjust judge said. And shall God not avenge His own elect who cry out day and night to Him, though He bears long with them? I tell you that He will avenge them speedily. Nevertheless, when the Son of Man comes, will He really find faith on the earth?"
Luke 11:5-13 And He said to them, “Which of you shall have a friend, and go to him at midnight and say to him, ‘Friend, lend me three loaves; for a friend of mine has come to me on his journey, and I have nothing to set before him’; and he will answer from within and say, ‘Do not trouble me; the door is now shut, and my children are with me in bed; I cannot rise and give to you’? I say to you, though he will not rise and give to him because he is his friend, yet because of his persistence he will rise and give him as many as he needs. "So I say to you, ask, and it will be given to you; seek, and you will find; knock, and it will be opened to you. For everyone who asks receives, and he who seeks finds, and to him who knocks it will be opened. If a son asks for bread from any father among you, will he give him a stone? Or if he asks for a fish, will he give him a serpent instead of a fish? Or if he asks for an egg, will he offer him a scorpion? If you then, being evil, know how to give good gifts to your children, how much more will your heavenly Father give the Holy Spirit to those who ask Him!"
James 5:15 And the prayer of faith will save the sick, and the Lord will raise him up. And if he has committed sins, he will be forgiven.