This excerpt is taken from Sheikh Abu Hamza Abdul Khaliq Siddiqi's book Sahi Fazail-e-Amaal.
On the Day of Judgment, the people of Hell will be told that the believers used to recite this prayer in the world
On the Day of Judgment, when the disbelievers are thrown into Hell, they will cry out in panic and distress, saying, "O our Lord! Take us out of here; if we commit sins again, surely we will be wrongdoers." But Allah will reject them and cast them away, and explaining the reason, He will say to them that in the world, My believing servants used to seek forgiveness and mercy from Me through their faith and deeds, while you used to mock their supplication. Then they will be shown a prayer of the believers which you used to ridicule:
﴿رَبَّنَا آمَنَّا فَاغْفِرْ لَنَا وَارْحَمْنَا وَأَنتَ خَيْرُ الرَّاحِمِينَ﴾
"O our Lord! We have believed, so forgive us and have mercy upon us. Indeed, You are the best of the merciful."
Reference: (23-Al-Mu’minun:109)
