Sunan Abi Dawud, Book 3, Hadith 867 (USC-MSA) ⓘ

‘Abd Allah (b. Masud) said: When any of you bows, he should spread his arms on his thighs and clap both his palms (Placing them between the knees), as if I am seeing the variation of the fingers of the Messenger of Allah.

حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، حَدَّثَنَا أَبُو مُعَاوِيَةَ، حَدَّثَنَا الأَعْمَشُ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، وَالأَسْوَدِ، عَنْ عَبْدِ اللَّهِ، قَالَ إِذَا رَكَعَ أَحَدُكُمْ فَلْيَفْرِشْ ذِرَاعَيْهِ عَلَى فَخِذِهِ وَلْيُطَبِّقْ بَيْنَ كَفَّيْهِ فَكَأَنِّي أَنْظُرُ إِلَى اخْتِلاَفِ أَصَابِعِ رَسُولِ اللَّهِ صلى الله عليه وسلم ‏.‏