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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
bayhaqi:12673 – Abū ʿAbdullāh al-Ḥāfiẓ And ʾAbū Saʿīd b. Abū ʿAmr > Abū al-ʿAbbās Muḥammad b. Yaʿqūb > Abū Bakr Muḥammad b. ʿAlī al-Warrāq > Muslim b. Ibrāhīm > Ḥarb b. Maymūn > ʿAwf > Abū Rajāʾ > ʿUmar

[Machine] Umar ibn Al-Khattab, may Allah have mercy on him, said: "May Allah have mercy on a man who provoked a slap on an orphan."  

البيهقي:١٢٦٧٣ – أَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ وَأَبُو سَعِيدِ بْنُ أَبِي عَمْرٍو قَالَا ثنا أَبُو الْعَبَّاسِ مُحَمَّدُ بْنُ يَعْقُوبَ ثنا أَبُو بَكْرٍ مُحَمَّدُ بْنُ عَلِيٍّ الْوَرَّاقُ ثنا مُسْلِمُ بْنُ إِبْرَاهِيمَ ثنا حَرْبُ بْنُ مَيْمُونٍ ثنا عَوْفٌ عَنْ أَبِي رَجَاءٍ قَالَ

قَالَ عُمَرُ بْنُ الْخَطَّابِ ؓ رَحِمَ اللهُ رَجُلًا ائْتَجَرَ عَلَى يَتِيمٍ بِلَطْمَةٍ  

See similar narrations below:

Collected by Suyūṭī