Prayers and Meditations — Paragraph 526
Source (Arabic)
بِهِ فَارْحَمْنِي يا أَرْحَمَ الَّراحِمِينَ، وَفِّقْ يا إِلهِي عِبادَكَ عَلَى نُصْرَةِ أَمْرِكَ ثُمَّ أَشْرِبْهُمْ ما تَحْيى
Translation
Thy will hath overruled my will, O my God, and I have shown forth what hath grievously vexed me. Have mercy, then, upon me, O Thou Who of all those who show mercy art the Most Merciful!