Ahmad recorded it (5/369). I say: Its chain of transmission is authentic. Al-Haythamī said (9/179): “Its narrators are narrators of the Ṣaḥīḥ collections.”

2. From Abū Ḥāzim, from Abū Hurayrah, attributed to the Prophet with the same wording. Al-Bazzār recorded it (2626). I say: Its chain of transmission is good, as al-Haythamī also stated. Al-Ḥākim recorded it (3/177) through another route from Abū Ḥāzim with the same report, but without mentioning al-Ḥasan. Its wording is: “I saw the Messenger of Allah, peace and blessings be upon him, carrying al-Ḥusayn ibn ʿAlī and saying: ‘O Allah, I love him, so love him.’” He said: “Its chain of transmission is authentic, though the two Shaykhs did not record it. A similar report concerning al-Ḥasan has also been narrated through a chain of transmission, and both have been preserved.” See the forthcoming hadith (2807).

There are also reports on this subject from a number of other Companions. Whoever wishes may consult Kashf al-Astār and Majmaʿ al-Zawāʾid.

Note: Among the errors of the commentator on Sunan al-Tirmidhī is his statement concerning the hadith under discussion (9/340): “Al-Tirmidhī alone recorded it!” Yet al-Bukhārī and Muslim both recorded it, as you have seen. He then did the reverse in al-Tirmidhī’s anomalous hadith, narrated earlier through Fuḍayl ibn Marzūq: