ENOfficial
Narrated As-Sa'ib bin Yazid: (While in the company of my parents) I was made to perform Hajj with Allah's Messenger (ﷺ) and I was a seven-year-old boy then. (Fath-ul-Bari, p.443, Vol.4)
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ يُونُسَ، حَدَّثَنَا حَاتِمُ بْنُ إِسْمَاعِيلَ، عَنْ مُحَمَّدِ بْنِ يُوسُفَ، عَنِ السَّائِبِ بْنِ يَزِيدَ، قَالَ حُجَّ بِي مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم وَأَنَا ابْنُ سَبْعِ سِنِينَ.
sunnah.com