Luke 2:37
and having been a widow for eighty-four years. She was never away from the temple; night and day she worshipped, fasting and praying.
Luke 11:8-13
I tell you, though he will not get up and give you anything because you are a friend of his, he will at least rise and give you whatever you want, because you persist.
Luke 18:7
And will not God see justice done to his elect who cry to him by day and night? Will he be tolerant to their opponents?
Ephesians 6:18
praying at all times in the Spirit with all manner of prayer and entreaty ??be alive to that, attend to it unceasingly, interceding on behalf of all the saints