It is narrated from Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with him) that al-Aqra' bin Habis came to the Prophet (peace and blessings be upon him), and Sayyiduna Abu Bakr (may Allah be pleased with him) said: O Messenger of Allah, appoint him as governor over his people. Sayyiduna Umar (may Allah be pleased with him) said: O Messenger of Allah, do not appoint him as governor. The two of them kept talking in the presence of the Prophet (peace and blessings be upon him) until their voices were raised. Sayyiduna Abu Bakr (may Allah be pleased with him) said to Sayyiduna Umar (may Allah be pleased with him): You only wanted to oppose me. He said: I did not intend to oppose you. Upon this, this verse was revealed: "O you who believe, do not raise your voices above the voice of the Prophet" [Surah al-Hujurat: 2]. After that, whenever Sayyiduna Umar (may Allah be pleased with him) spoke in the presence of the Prophet (peace and blessings be upon him), he would speak in such a low voice that he (peace and blessings be upon him) had to ask him again.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13872