(44) باب أَعْضَاءِ السُّجُودِ وَالنَّهْىِ عَنْ كَفِّ الشَّعْرِ، وَالثَّوْبِ، وَعَقْصِ الرَّأْسِ، فِي الصَّلاَة
Ibn 'Abbas reported:
The Messenger of Allah (ﷺ) had been commanded to prostrate on seven (bones) and forbidden to fold back hair and clothing.
Reference: Sahih Muslim 490 c
In-book reference: Book 4, Hadith 259
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 993