عَنْ أَبِي وَائِلٍ رَضِيَ اللَّهُ عَنْهُ قَالَ أَتَى عَلِيًّا رَضِيَ اللَّهُ عَنْهُ رَجُلٌ فَقَالَ يَا أَمِيرَ الْمُؤْمِنِينَ إِنِّي عَجَزْتُ عَنْ مُكَاتَبَتِي فَأَعِنِّي فَقَالَ عَلِيٌّ رَضِيَ اللَّهُ عَنْهُ أَلَا أُعَلِّمُكَ كَلِمَاتٍ عَلَّمَنِيهِنَّ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ لَوْ كَانَ عَلَيْكَ مِثْلُ جَبَلِ صِيرٍ دَنَانِيرَ لَأَدَّاهُ اللَّهُ عَنْكَ قُلْتُ بَلَى قَالَ قُلْ اللَّهُمَّ اكْفِنِي بِحَلَالِكَ عَنْ حَرَامِكَ وَأَغْنِنِي بِفَضْلِكَ عَمَّنْ سِوَاكَ
It is narrated from Sayyiduna Abu Wa'il (may Allah be pleased with him) that a man came to Sayyiduna Ali (may Allah be pleased with him) and said: O Commander of the Faithful! I have become unable to fulfill my contract of manumission, so please help me. Sayyiduna Ali (may Allah be pleased with him) said: Shall I teach you the words which the Messenger of Allah (peace and blessings be upon him) taught me? Even if you have a debt as much as the mountain of Seer in dinars, Allah Almighty will pay it off for you. He said: Yes, of course. He (Ali) said: Recite this supplication: "Allahumma akfini bihalalika 'an haramika wa aghnini bifadlika 'amman siwaka" (O Allah! Suffice me with what You have made lawful instead of what You have made unlawful, and make me independent by Your grace from all besides You).