Mishkatul Masabih — Hadith #40119

He said, Rasulullah (may peace be upon him) came out one night and found Abu Bakr praying. He was reciting the Quran in a low voice. Then he was passing by 'Umar. Umar (RA) recited the Quran aloud was doing Abu Qatadah said, (in the morning) when Abu Bakr and 'Umar both gathered at the service of the Messenger; He said, Abu Bakr! I was passing you by tonight. You were reciting the Holy Quran in a low voice. Abu Bakr pleaded, O Messenger of God! I was telling him to whom I was praying. Then he said to 'Umar, O 'Umar! (Tonight) I was going to you too. You were reciting the Quran in a loud voice in prayer. 'Umar pleaded, O Messenger of Allah! I pray in a loud voice I was waking up the sleeping people and driving away the devil. Rasulullah (to Abu Bakr after listening to the two people) said, Abu Bakr! You raise your voice a little higher. (He said to 'Umar) 'Umar! You lower your voice a little more. (Abu Dawud, Tirmidhi) [1]