From Mme. Khan’s Pilgrim’s Notes, Feb 23, 1938:
To be prayed or repeated 1000 times between midnight and dawn for 9 or 19 nights (though to use the prayer once daily or even 9 or 19 times is enough). It seems infallible, even marvellous in power. ‘Abdu’l-Bahá said it for 3 days just before WW2 ended:
O God Our Deliverer, whom we invoke in times of extreme need, danger, or crisis!