Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
ibnhibban:875 – Muḥammad b. al-Ḥasan b. Qutaybah > Yazīd b. Mawhab > Ibn Wahb > Maʿrūf b. Sūwayd > ʿAlī b. Rabāḥ > Abū Hurayrah

[Machine] The Messenger of Allah ﷺ said, "Beware of the supplication of the oppressed."  

ابن حبّان:٨٧٥ – أَخْبَرَنَا مُحَمَّدُ بْنُ الْحَسَنِ بْنِ قُتَيْبَةَ قَالَ حَدَّثَنَا يَزِيدُ بْنُ مَوْهَبٍ قَالَ أَخْبَرَنَا ابْنُ وَهْبٍ عَنْ مَعْرُوفِ بْنِ سُوَيْدٍ قَالَ سَمِعْتُ عَلِيَّ بْنَ رَبَاحٍ يَقُولُ سَمِعْتُ أَبَا هُرَيْرَةَ يَقُولُ

قَالَ رَسُولُ اللَّهِ ﷺ «اتَّقُوا دَعْوَةَ الْمَظْلُومِ»  

See similar narrations below:

Collected by Aḥmad, Suyūṭī
ahmad:12549 – Yaḥyá b. Isḥāq > Yaḥyá b. Yyūb > Abū ʿAbdullāh al-Asadī > Anas b. Mālik

[Machine] The Messenger of Allah ﷺ said: "Beware of the supplication of the oppressed, even if he is a disbeliever, for there is no barrier between it and Allah."  

أحمد:١٢٥٤٩ – حَدَّثَنَا يَحْيَى بْنُ إِسْحَاقَ قَالَ أَخْبَرَنِي يَحْيَى بْنُ أيُّوبَ قَالَ أَخْبَرَنِي أَبُو عَبْدِ اللهِ الْأَسَدِيُّ قَالَ سَمِعْتُ أَنَسَ بْنَ مَالِكٍ يَقُولُ

قَالَ رَسُولُ اللهِ ﷺ اتَّقُوا دَعْوَةَ الْمَظْلُومِ وَإِنْ كَانَ كَافِرًا فَإِنَّهُ لَيْسَ دُونَهَا حِجَابٌ