Abu Dawud Book 36, Hadith Number 4788.

Narated By Abdullah ibn ash-Shikhkhir : I went with a deputation of Banu Amir to the apostle of Allah (PBUH), and we said: You are our lord (sayyid). To this he replied: The lord is Allah, the Blessed and Exalted. Then we said: And the one of us most endowed with excellence and superiority. To this he replied: Say what you have to say, or part of what you have to say, and do not let the devil make you his agents.