Muḥammad ibn Ismāʿīl al-Tirmidhī related: “Ahmad ibn al-Ḥasan al-Tirmidhī and I were with Aḥmad ibn Ḥanbal when Ahmad said to him, ‘Abū ʿAbd Allāh, they mentioned the hadith scholars to Ibn Abī Qutilah in Mecca, and he replied, “The hadith scholars are a wicked folk.”’
At this, Abū ʿAbd Allāh rose, shook his cloak and kept saying, ‘Heretic! Heretic!’ then went inside the house.
Al-Ṭabarānī said: Muḥammad ibn Mūsā ibn Ḥammād recited to us these verses composed by Muḥammad ibn ʿAbd Allāh ibn Ṭāhir:
Ibn Ḥanbal has become a trial acclaimed by God,
And love for Ahmad marks the true devotee.
If ever you find a man belittling Ahmad,
Know that his veils will soon be torn. ⦗1⦘
ʿUthmān ibn Saʿīd al-Dāramī said: “I saw Aḥmad ibn Ḥanbal disapprove of being called by the kunya ‘Abū al-Qāsim.’” ⦗2⦘
(1) The two verses are cited in Tarikh Baghdad, vol. 4, pp. 420–421; there the first line reads “mihna mamuna” (a secured ordeal) instead of “mardiyya” (pleasing). They also appear in Tabaqat al-Shafi‘iyya, vol. 2, p. 33.
(2) Scholars have differed on adopting the Prophet’s kunya. Some declare it impermissible, invoking the agreed‐upon hadith of Jabir: “Give yourselves my name, but do not take my kunya.” This opinion is reported from al-Hasan, Ibn Sirin, and Tawus, and it is the position of al-Shafi‘i, who rules that no one may be called Abu al-Qasim, whether or not his personal name is Muhammad.
Other jurists merely dislike combining the Prophet’s personal name with his kunya, yet permit the kunya Abu al-Qasim when the person’s name is not Muhammad or Ahmad. Their evidence includes the report recorded by al-Tirmidhi (no. 2843) in which Abu Hurayra relates that the Prophet forbade anyone to unite his name and kunya by calling himself “Muhammad Abu al-Qasim.” Abu Dawud likewise transmits from Jabir that the Prophet said: “Whoever is named after me must not adopt my kunya, and whoever adopts my kunya must not take my name.”
Abu Dawud (no. 4966) and al-Tirmidhi (no. 2846), with an authentic chain, narrate that ‘Ali asked, “Messenger of Allah, if a son is born to me after you, may I name him Muhammad and give him your kunya?” He replied, “Yes,” granting a special dispensation to me.
Some scholars therefore allowed combining the two, arguing that the prohibition applied only during the Prophet’s lifetime so as to avoid confusion; this view is related from Malik.
Among those who in fact combined both the name and the kunya were Muhammad b. al-Hanafiyya, Muhammad b. Abi Bakr al-Siddiq, Muhammad b. Ja‘far b. Abi Talib, Muhammad b. Sa‘d b. Abi Waqqas, Muhammad b. al-Ash‘ath, and Muhammad b. Hatib.