Musnad Ahmad 30:2470

Yahya narrated to us, from Ibn ‘Ajlan, who said: I heard my father, from Abu Hurayrah, from the Prophet (peace and blessings of Allah be upon him), who said: "Do not combine my name and my kunyah (agnomen). For I am Abu al-Qasim; Allah, the Mighty and Majestic, gives, and I distribute."