The Forty Hadith Qudsi #31
forty_hadith_qudsi:31عَنْ جُنْدُبٍ رَضِيَ اللهُ عَنْهُ : أَنَّ رَسُولَ اللهِ صَلَّى الله عَلَيْهِ وَ سَلَّمَ حَدَّثَ (أَنْ رجُلاً قال : واللهِ لا يَغْفِرُ اللهُ لِفُلانٍ وإِنَّ اللهَ تَعَالَى قَالَ : مَنْ ذَا الَّذِي يَتَأَلَّى عَلَيَّ أَنْ لا أَغْفِرَ لِفُلان،فَإِنِّي قَدْ غَفَرْتُ لِفُلانٍ، وأَحْبَطْتُ عَمَلَكَ (أَوْ كَمَا قَال رواه مسلم
A man said: By Allah, Allah will not forgive So-and-so. At this Allah the Almighty said: Who is he who swears by Me that I will not forgive So-and-so? Verily I have forgiven So-and-so and have nullified your ). (1) A similar Hadith, which is given by Abu Dawud, indicates that the person referred to was a goldly man whose previous good deeds were brought to nought through presuming to declare that Allah would not forgive someone's bad deeds. It was related by Muslim.
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