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.
abudawud:735ʿAmr b. ʿUthmān > Baqiyyah > ʿUtbah > ʿAbdullāh b. ʿĪsá > al-ʿAbbās b. Sahl al-Sāʿidī > Abū Ḥumayd Bihadhā al-Ḥadīth

When he (the Prophet) prostrated he kept his thighs wide and did not let his belly touch the thighs. Abu Dawud says that Ibn Mubarak narrated this hadith from ‘Abbas b. Sahl, which he did not remember well. It is thought that he has mentioned ‘Isa b. ‘Abd Allah, ‘Abbas b. Sahl and Abu Humaid al-Sa’idi.  

أبو داود:٧٣٥حَدَّثَنَا عَمْرُو بْنُ عُثْمَانَ حَدَّثَنَا بَقِيَّةُ حَدَّثَنِي عُتْبَةُ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ عِيسَى عَنِ الْعَبَّاسِ بْنِ سَهْلٍ السَّاعِدِيِّ عَنْ أَبِي حُمَيْدٍ بِهَذَا الْحَدِيثِ قَالَ

وَإِذَا سَجَدَ فَرَّجَ بَيْنَ فَخِذَيْهِ غَيْرَ حَامِلٍ بَطْنَهُ عَلَى شَىْءٍ مِنْ فَخِذَيْهِ  

قَالَ أَبُو دَاوُدَ رَوَاهُ ابْنُ الْمُبَارَكِ أَخْبَرَنَا فُلَيْحٌ سَمِعْتُ عَبَّاسَ بْنَ سَهْلٍ يُحَدِّثُ فَلَمْ أَحْفَظْهُ فَحَدَّثَنِيهِ أُرَاهُ ذَكَرَ عِيسَى بْنَ عَبْدِ اللَّهِ أَنَّهُ سَمِعَهُ مِنْ عَبَّاسِ بْنِ سَهْلٍ قَالَ حَضَرْتُ أَبَا حُمَيْدٍ السَّاعِدِيَّ بِهَذَا الْحَدِيثِ