Narrated 'Abdullah bin Az-Zubair:
Al-Aqra' bin Habis arrived to meet the Prophet (ﷺ) - 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 (ﷺ) 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 (ﷺ), 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.