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:2718Abū ʿAbdullāh al-Ḥāfiẓ > Abū Jaʿfar Muḥammad b. Ṣāliḥ b. Hāniʾ > Yaʿqūb b. Yūsuf al-Akhram > Isḥāq b. Ibrāhīm And ʾAbū Kurayb > Abū Usāmah > ʿAbd al-Ḥamīd b. Jaʿfar > Muḥammad b. ʿAmr b. ʿAṭāʾ > Abū Ḥumayd al-Sāʿidī

[Machine] I heard Abu Humaid Al-Sa'id saying: "The Messenger of Allah ﷺ used to recite a supplication when he got up to perform prayer, then he would prostrate to the ground and place his arms on his sides, and spread his fingers and toes."  

البيهقي:٢٧١٨أَخْبَرَنَا أَبُو عَبْدِ اللهِ الْحَافِظُ أنبأ أَبُو جَعْفَرٍ مُحَمَّدُ بْنُ صَالِحِ بْنِ هَانِئٍ ثنا يَعْقُوبُ بْنُ يُوسُفَ الْأَخْرَمُ ثنا إِسْحَاقُ بْنُ إِبْرَاهِيمَ وَأَبُو كُرَيْبٍ قَالَا ثنا أَبُو أُسَامَةَ ثنا عَبْدُ الْحَمِيدِ بْنُ جَعْفَرٍ حَدَّثَنِي مُحَمَّدُ بْنُ عَمْرِو بْنِ عَطَاءٍ قَالَ

سَمِعْتُ أَبَا حُمَيْدٍ السَّاعِدِيَّ يَقُولُ كَانَ رَسُولُ اللهِ ﷺ إِذَا قَامَ إِلَى الصَّلَاةِ الْحَدِيثَ وَقَالَ فِيهِ ثُمَّ هَوَى إِلَى الْأَرْضِ سَاجِدًا ثُمَّ جَافَى عَضُدَيْهِ عَنْ إِبِطَيْهِ وَفَتَحَ أَصَابِعَ رِجْلَيْهِ  


See similar narrations below:

Collected by Nasāʾī's Kubrá
nasai-kubra:692Muḥammad b. Bashhār > Yaḥyá b. Saʿīd > ʿAbd al-Ḥamīd b. Jaʿfar > Muḥammad b. ʿAṭāʾ > Abū Ḥumayd al-Sāʿidī

"When the Prophet ﷺ fell to the ground during prostration, he held his arms away from his sides and bent his toes." (Using translation from Nasāʾī 1101)  

الكبرى للنسائي:٦٩٢أَخْبَرَنَا مُحَمَّدُ بْنُ بَشَّارٍ قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ قَالَ حَدَّثَنَا عَبْدُ الْحَمِيدِ بْنُ جَعْفَرٍ قَالَ حَدَّثَنِي مُحَمَّدُ بْنُ عَطَاءٍ عَنْ أَبِي حُمَيْدٍ السَّاعِدِيِّ قَالَ

«كَانَ النَّبِيُّ ﷺ إِذَا أَهَوَى إِلَى الْأَرْضِ سَاجِدًا جَافَى عَضُدَيْهِ عَنْ إِبِطَيْهِ وَفَتِخَ أَصَابِعَ رِجْلَيْهِ»