Prayers and Meditations — Paragraph 590
Source (Arabic)
مُعْرِضٍ إِنَّكَ أَنْتَ المُهَيْمِنُ بِسُلْطانِكَ لا إِلهَ إِلاَّ أَنْتَ المُقْتَدِرُ القَدِيرُ.
Translation
Thou, truly, art the Help in Peril through the power of Thy sovereignty. No God is there save Thee, the Almighty, the Most Powerful.