Al-Kāfi - Volume 4 > Hajj of the Holy Prophet, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause
Hadith #3

3ـ أَحْمَدُ بْنُ مُحَمَّدٍ عَنِ الْحَسَنِ بْنِ عَلِيٍّ عَنْ يُونُسَ بْنِ يَعْقُوبَ عَنْ عُمَرَ بْنِ يَزِيدَ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ السَّلاَم) قَالَ حَجَّ رَسُولُ الله (صلَّى اللهُ عَلَيْهِ وَآلِه) عِشْرِينَ حَجَّةً.

3. Ahmad ibn Muhammad has narrated from al-Hassan ibn Ali from Yunus ibn Ya’qub from ‘Umar ibn Yazid who has said the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said that the Messenger of Allah, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause, performed Hajj a total of twenty times.”