Reference: Siyar A’laam an-Nubalaa – Volume 13, Page 247
Ibn Abee Haatim said he heard Yoonus ibn ‘Abdil-A’laa say:
Abu Zur’ah and Abu Haatim are the two imaams of Khuraasaan.
…and he then supplicated for them, and said:
Their presence entails the wellbeing of the Muslims.