In this, he followed al-Bukhari in al-Tarikh (4/2/209). Neither of them referred to him by the agnomen Abu Tumah, nor did either make the slightest indication of this. Ibn Hibban likewise followed them both in this, mentioning him among the trustworthy Followers of the Successors (7/575).

Second: when they gave his biographical notice under the agnomens, as mentioned above, neither of them indicated that he was the Hilal whose notice had preceded under the names. Third: a careful examination of their two biographical notices shows that they do not belong to the same generation. One who heard Ibn Umar would be a Successor, whereas one who narrated from Umar ibn Abd al-Aziz—who was himself a Successor—would ordinarily be among the Followers of the Successors. This does not preclude their being of the same generation, in which case it would be a narration of contemporaries from one another, or at least a narration of elders from those younger in age. All of this is possible in my view, but the matter requires proof. I therefore continued my investigation and research, especially after seeing that later scholars had considered them to be one and the same. I then found the following:

First: Imam Ahmad said in al-Ilal wa-Marifat al-Rijal (1/295): “Abu Tumah was from Syria. Abd al-Aziz ibn Umar narrated from him, as did Ibn Jabir and Ibn Lahi'ah.” By mentioning Abd al-Aziz ibn Umar among those who narrated from Abu Tumah, he indicated that he was Hilal himself. This is supported by my second point: I found Imam Ahmad saying in al-Musnad (2/25): “Waki narrated to us: Abd al-Aziz ibn Umar ibn Abd al-Aziz narrated to us from Abu Tumah, their client, and from Abd al-Rahman ibn Abd Allah al-Ghafiqi, that the two of them heard Ibn Umar say: ‘The Messenger…’”