عن السَّائب بن يزيد رضي الله عنهما قال: «حُجَّ بي مع رسول الله صلى الله عليه وسلم في حجة الوداع، وأنا ابن سبع سنين».
[صحيح] - [رواه البخاري]
As-Sā’ib ibn Yazīd (may Allah be pleased with him) reported: I was taken to perform pilgrimage with the Messenger of Allah (may Allah’s peace and blessings be upon him) in the Farewell Pilgrimage, when I was seven years old.
Sahih/Authentic. - [Al-Bukhari]
As-Sā’ib ibn Yazīd (may Allah be pleased with him) was a young Companion. He preformed Hajj with his family during the lifetime of the Prophet (may Allah's peace and blessings be upon him) in the Farewell Pilgrimage. The Prophet (may Allah's peace and blessings be upon him) approved that young children perform Hajj and said that they would be rewarded for it. However, it is considered a voluntary Hajj, and they must perform the obligatory Hajj after reaching puberty. The child does in his Hajj the same rituals that the adult does, including Ihrām, not wearing form-fitting clothes, saying the Talbiyah, and so on. If the child is unable to do any of the rituals, then his guardian - such as his father or mother - should do it on his behalf.