Hadith 6:831
Hafs narrated to us, from Hajjaj, from Nafi’, who said: A *lahd* (niche) was made for the grave of the Messenger of Allah, may Allah bless him and grant him peace, and for Abu Bakr and Umar. Then you boasted.
حدثنا حفص عن حجاج عن نافع قال لحد لرسول الله صلى الله عليه وسلم قبره ولأبي بكر وعمر ثم تفاخرتم