Ibn Abbas reported: The Messenger of Allah, peace and blessings be upon him, said, “Two supplications have no barrier between them and Allah: the supplication of the oppressed, and the supplication of a man for his brother behind his back.”
Source: al-Mu’jam al-Kabīr lil-Ṭabarānī 11232
Grade: Sahih (authentic) according to Al-Suyuti
عَنِ ابْنِ عَبَّاسٍ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ دَعْوَتَانِ لَيْسَ بَيْنَهُمَا وَبَيْنَ اللَّهِ حِجَابٌ دَعْوَةُ الْمَظْلُومِ وَدَعْوَةُ الْمَرْءِ لِأَخِيهِ بِظَهْرِ الْغَيْبِ
11/119 المعجم الكبير للطبراني
4191 المحدث السيوطي خلاصة حكم المحدث صحيح في الجامع الصغير
