Shaikh ʿAbd Allāh Al-Bukhāri said:

Abū Al-Faḍl Al-Tamīmī narrated about Imām Aḥmad ibn Ḥanbal, may Allāh have mercy on him, that he would supplicate while in prostration:

O Allāh, anyone from this ummah upon other than the truth that thinks he is upon the truth, make him return to the truth to become [one] of the People of the Truth.

Al-Bidāyah wa-l-Nihāyah (vol. 14, p. 390); also see Tārīkh Al-Baghdād (vol. 10, p. 286) and Ṣifah Al-Ṣafwah (vol. 1, p. 484).