Narrated Ibn Abi Mulaika:
The two righteous persons were about to be ruined. They were Abu Bakr and `Umar who raised their voices in the presence of the Prophet (s.a.w.a.) when a mission from Bani Tamim came to him. One of the two recommended Al-Aqra' bin Habeas, the brother of Bani Mujashi (to be their governor) while the other recommended somebody else. (Nafi`, the sub-narrator said, I do not remember his name). Abu Bakr said to `Umar, "You wanted nothing but to oppose me!" `Umar said, "I did not intend to oppose you." Their voices grew loud in that argument, so Allah revealed: 'O you who believe! Raise not your voices above the voice of the Prophet.' (49.2) Ibn Az-Zubair said, "Since the revelation of this Verse, `Umar used to speak in such a low tone that the Prophet (s.a.w.a.) had to ask him to repeat his statements." But Ibn Az-Zubair did not mention the same about his (maternal) grandfather (i.e. Abu Bakr).
Narrated Ibn Abi Mulaika:
Once the two righteous men, i.e., Abu Bakr and `Umar were on the verge of destruction (and that was because): When the delegate of Bani Tamim came to the Prophet, one of them (either Abu Bakr or `Umar) recommended Al-Aqra' bin H`Abis at-Tamimi Al-Hanzali, the brother of Bani Majashi (to be appointed as their chief), while the other recommended somebody else. Abu Bakr said to `Umar, "You intended only to oppose me." `Umar said, "I did not intend to oppose you!" Then their voices grew louder in front of the Prophet (s.a.w.a.) whereupon there was revealed: 'O you who believe! Do not raise your voices above the voice of the Prophet..a great reward.' (49.2-3) Ibn Az-Zubair said, 'Thence forward when `Umar talked to the Prophet, he would talk like one who whispered a secret and would even fail to make the Prophet (s.a.w.a.) hear him, in which case the Prophet (s.a.w.a.) would ask him (to repeat his words).
Narrated 'Abdullah bin Az-Zubair:
"Al-Aqra' bin Habis arrived to meet the Prophet (s.a.w.a.)" - he said - "so Abu Bakr said: 'O Messenger of Allah! Appoint him over his people.' 'Umar said: 'Do not appoint him O Messenger of Allah!' They continued talking before the Prophet (s.a.w.a.) until they raised their voices. Abu Bakr said to 'Umar: 'You only wanted to contradict me.' So ['Umar] said: 'I did not want to contradict you.'" He said: "So this Ayah was revealed: 'O you who believe! Do not raise your voices above the voice of the Prophet (49:2).'" He said: "After that, when 'Umar spoke before the Prophet (s.a.w.a.), his speech could not be heard until he told him he could not understand him." He (one of the narrators) said: "And Ibn Az-Zubair did not mention his grandfather" meaning Abu Bakr.