Ibn Abbas reported the Prophet ﷺ as saying: I have been commanded - according to the version of Hammad: Your Prophet ﷺ was commanded - to prostrate on seven (bones), and not to fold back the hair or the clothing.
عَنِ النَّبِيِّ ﷺ قَالَ أُمِرْتُ قَالَ حَمَّادٌ أُمِرَ نَبِيُّكُمْ ﷺ أَنْ يَسْجُدَ عَلَى سَبْعَةٍ وَلاَ يَكُفَّ شَعْرًا وَلاَ ثَوْبًا