He did not fight; rather, he stayed behind with the army’s baggage train. That is how the two reports are reconciled.

Anas also said:
“The Prophet ﷺ gave me the kunya ‘Abū Ḥamzah’ because of a vegetable I had picked.” (1)

ʿAlī ibn Zayd—who is somewhat weak—narrated from Ibn al-Musayyib, from Anas:
“When the Messenger of Allah ﷺ arrived in Madinah I was eight years old. My mother took me by the hand and led me to him, saying, ‘O Messenger of Allah, there is no man or woman among the Helpers who has not presented you with a gift. I have nothing to offer you except this son of mine, so take him, and let him serve you for as long as you wish.’
‘I served him for ten years,’ Anas continued, ‘and he never struck me, never insulted me, and never even frowned in my face.’
Al-Tirmidhī recorded this report. (2)

ʿIkrimah ibn ʿAmmār related: “Isḥāq ibn ʿAbd Allāh ibn Abī Ṭalḥah told us, Anas told us:
‘Umm Sulaym brought me to the Messenger of Allah ﷺ, having wrapped me in half of her head-scarf and veiled me with the other half. She said, “O Messenger of Allah, this is Unays, my son. I have brought him so that he may serve you—pray to Allah for him.”
He said, “O Allah, increase his wealth and his children.”
By Allah, my wealth is indeed plentiful, and today my children and grandchildren number about one hundred.’” (3)

A similar narration was transmitted by Jaʿfar ibn Sulaymān from Thābit.

Another version was reported by Shuʿbah, from Qatādah, from Anas, that Umm Sulaym said: “O Messenger of—