Luke 2:37
and had been a widow about eighty four years; who departed not from the temple; serving God with fastings and prayers night and day.
Luke 11:8-13
I tell you, tho' 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 wants.
Luke 18:7
and will not God do justice for his elect that cry to Him day and night, though He bear long with them.
Ephesians 6:18
praying at all seasons with all prayer and supplication in the Spirit, and watching thereunto with all perseverance, and intercession for all the saints;