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.
bayhaqi:2544[Chain 1] Abū Saʿd ʿAbd al-Malik b. Abū ʿUthmān al-Zāhid > Abū Muḥammad Yaḥyá b. Manṣūr al-Qāḍī [Chain 2] Abū Ṣāliḥ b. Abū Ṭāhir al-ʿAnbarī > Jaddī Yaḥyá b. Manṣūr al-Qāḍī > Aḥmad b. Salamah > Qutaybah b. Saʿīd > Abū ʿAwānah > Abū Yaʿfūr > Muṣʿab b. Saʿd

[Machine] I prayed next to Saad, and I cupped my hands and placed them between my thighs. Then I struck my hands, and he said. Then I prayed again next to him, and I cupped my hands and placed them between my thighs. He struck my hands and said, "O my son, we used to do this, and we were commanded to strike with the palms on the knees."  

البيهقي:٢٥٤٤حَدَّثَنَا أَبُو سَعْدٍ عَبْدُ الْمَلِكِ بْنُ أَبِي عُثْمَانَ الزَّاهِدُ أنبأ أَبُو مُحَمَّدٍ يَحْيَى بْنُ مَنْصُورٍ الْقَاضِي (ح) وَأَخْبَرَنَا أَبُو صَالِحِ بْنُ أَبِي طَاهِرٍ الْعَنْبَرِيُّ أنبأ جَدِّي يَحْيَى بْنُ مَنْصُورٍ الْقَاضِي ثنا أَحْمَدُ بْنُ سَلَمَةَ ثنا قُتَيْبَةُ بْنُ سَعِيدٍ ثنا أَبُو عَوَانَةَ عَنْ أَبِي يَعْفُورٍ عَنْ مُصْعَبِ بْنِ سَعْدٍ قَالَ

صَلَّيْتُ إِلَى جَنْبِ سَعْدٍ فَطَبَّقْتُ بِيَدِيَّ فَجَعَلْتُهُمَا بَيْنَ رُكْبَتِيَّ فَضَرَبَ بِيَدِيَّ قَالَ ثُمَّ صَلَّيْتُ مَرَّةً أُخْرَى إِلَى جَنْبِهِ فَطَبَّقْتُ بِيَدِيَّ فَجَعَلْتُهُمَا بَيْنَ رُكْبَتِيَّ قَالَ فَضَرَبَ بِيَدِيَّ وَقَالَ يَا بُنِيَّ إِنَّا كُنَّا نَفْعَلُ هَذَا فَأُمِرْنَا أَنْ نَضْرِبَ بِالْأَكُفِّ عَلَى الرُّكَبِ  

رَوَاهُ مُسْلِمٌ فِي الصَّحِيحِ عَنْ قُتَيْبَةَ وَغَيْرِهِ وَزَادَ إِنَّا نُهِينَا عَنْ هَذَا وَأُمِرْنَا أَنْ نَضْرِبَ بِالْأَكُفِّ عَلَى الرُّكَبِ وَأَخْرَجَهُ مِنْ حَدِيثِ الزُّبَيْرِ بْنِ عَدِيٍّ عَنْ مُصْعَبِ بْنِ سَعْدٍ