Narrated `Abdullah bin Az-Zubair: A group of Bani Tamim came to the Prophet (and requested him to appoint a governor for them). Abu Bakr said, Appoint Al-Qaqa bin Mabad. `Umar said, Appoint Al-Aqra' bin Habeas. On that Abu Bakr said (to `Umar). You did not want but to oppose me! `Umar replied I did not intend to oppose you! So both of them argued till their voices grew loud. So the following Verse was revealed: 'O you who believe! Be not for ward......' (49.1)