(152) بَابُ وَضْعِ الْيَدَيْنِ عَلَى الرُّكْبَتَيْنِ
'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(ﷺ).
Reference: Sunan Abi Dawud 868
In-book reference: Book 2, Hadith 478
English translation: Book 2, Hadith 867