Narrated Ibn Abi Mulaika: `Abdullah bin Az-Zubair said that a group of riders belonging to Banu Tamim came to the Prophet, Abu Bakr said (to the Prophet ), Appoint Al-Qa'qa bin Mabad bin Zurara as (their) ruler. `Umar said (to the Prophet). No! But appoint Al-Aqra bin H`Abis. Thereupon Abu Bakr said (to `Umar). You just wanted to oppose me. `Umar replied. I did not want to oppose you. So both of them argued so much that their voices became louder, and then the following Divine Verses were revealed in that connection:-- O you who believe ! Do not be forward in the presence of Allah and His Apostle... (till the end of Verse)...(49.1)