Luke 2:37
And then a widow, till she had reached the age of eighty-four. She never left the Temple Courts, but, fasting and praying, worshiped God night and day.
Luke 11:8-13
I tell you that, even though he will not get up and give him anything because he is a friend, yet because of his persistence he will rouse himself and give him what he wants.
Luke 18:7
And God--will not he see that his own People, who cry to him night and day, have justice done them--though he holds his hand?
Ephesians 6:18
Pray in spirit at all times. Be intent upon this, with unwearying perseverance and supplication for all Christ's People- -