This prayer revealed by Baha'u'llah for Mirza Abdu'l Fazl, when the latter went into exile with the promise that if he would use at any juncture, help would come.
See: Star of the West, Sept. 1923, Vol 14, No.6, Pg. 166
O Thou help me...
It was in 1912 that Dr. Ali Kuli Khan - preparing for the visit of Abdu'l-Baha to Washington - began to consider the questions he would ask Him upon His arrival. And, thinking it over, Dr. Khan realized that the one thing he wanted most to know was some prayer he might utter quickly and from deep within his heart, when the moment came when, as the representative of his country (then Persia) in Washington he must make some instant diplomatic decision. When these moments came, as they did frequently - Dr. Khan felt that while he always sincerely did his best, his wisdom was very limited and finite. If only he might have a prayer that would draw to him a greater wisdom... Ah, if he only might have such a prayer.
So the day came when Abdu'l-Baha was to arrive and Dr. Khan, accompanied by the Washington believers, drove to the station to meet Him. The greeting was warm and deeply moving, and Khan's heart was still filled with this one question he wanted most to ask the Master. And they were perhaps halfway back, driving up Pennsylvania Avenue, when Abdu'l-Baha suddenly told Khan this story:
It had happened when Baha'u'llah had been gone from Baghdad for some two years. At that time no one knew where He was and all hearts were sick with the fear that they never would see Him again. At this time Abdu'l- Baha was a small boy, and the continued absence of His Beloved Father had become unendurable. So, one night, all night long, the little boy (whom, even then, Baha'u'llah referred to as The Master) paced restlessly up and down saying, shouting, beseeching,
And Dr. Khan knew the cry that he, too, might utter in his moments of need, "Ya Allah el Mustaghas," (which I am told means: Oh, Thou, help me in my extremity!).
This was told me by Ali Kuli Khan at Green-Acre in 1933