Luke 18:1 And he spake a parable unto them to this end, that men ought always to pray, and not to faint;
Luke 11:5-8 And he said unto them, Which of you shall have a friend, and shall go unto him at midnight, and say unto him, Friend, lend me three loaves; For a friend of mine in his journey is come to me, and I have nothing to set before him? And he from within shall answer and say, Trouble me not: the door is now shut, and my children are with me in bed; I cannot rise and give thee. I say unto you, Though he will not rise and give him, because he is his friend, yet because of his importunity he will rise and give him as many as he needeth.
Ephesians 6:18 Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;
Genesis 32:26 And he said, Let me go, for the day breaketh. And he said, I will not let thee go, except thou bless me.
Luke 6:12 And it came to pass in those days, that he went out into a mountain to pray, and continued all night in prayer to God.