مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2515
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه) that the Messenger of Allah (ﷺ) said: “I was commanded to prostrate on seven bones and not to tuck up my hair or garment." And on another occasion he said: Your Prophet (ﷺ) was commanded to prostrate on seven bones, and not to tuck up his hair or garment.
Musnad Ahmad 2527Its isnad is saheeh, al-Bukhari (809) and Muslim (490)]