كتاب الحج
11
The Book of Hajj
As-Sai'b bin Yazid (May Allah be pleased with him) reported:
I was seven years old when I was taken to perform Hajj (pilgrimage). This was during the time the Messenger of Allah (ﷺ) performed the Hajjat-ul-Wada' (Farewell Pilgrimage).

[Al- Bukhari].

وعن السائب بن يزيد رضي الله عنه، قال‏:‏ حج بي مع رسول الله صلى الله عليه وسلم في حجة الوداع وأنا ابن سبع سنين‏.‏ ‏(‏‏(‏رواه البخاري‏)‏‏)‏‏.‏
Sunnah.com reference : Book 11, Hadith 11
Arabic/English book reference : Book 11, Hadith 1281