The Rites of Hajj (Kitab Al-Manasik Wa'l-Hajj)
Dawud :: Book 10 : Hadith 1789
Narrated Sa'id ibn al-Musayyab:
A man from the Companions of the Prophet (peace_be_upon_him) came to Umar ibn al-Khattab (may Allah be pleased with him). He bore witness before him that when he (the Prophet) was suffering from a disease of which he died he heard the Apostle of Allah (peace_be_upon_him) prohibiting performing of umrah before hajj.