The Prophet (S) said to Abu Bakr: "I passed by you while you were reciting and your voice was low." He said: "I let He who, I was consulting hear." He said: "Raise your voice." Then he said to Umar: "I passed by while you were reciting and your voice was loud." So he said: "I repel drowsiness and keep Ash-Shaitan away." So he said: "Lower your voice."  

أَنَّ النَّبِيَّ ﷺ قَالَ لأَبِي بَكْرٍ مَرَرْتُ بِكَ وَأَنْتَ تَقْرَأُ وَأَنْتَ تَخْفِضُ مِنْ صَوْتِكَ فَقَالَ إِنِّي أَسْمَعْتُ مَنْ نَاجَيْتُ قَالَ ارْفَعْ قَلِيلاً وَقَالَ لِعُمَرَ مَرَرْتُ بِكَ وَأَنْتَ تَقْرَأُ وَأَنْتَ تَرْفَعُ صَوْتَكَ قَالَ إِنِّي أُوقِظُ الْوَسْنَانَ وَأَطْرُدُ الشَّيْطَانَ قَالَ اخْفِضْ قَلِيلاً قَالَ وَفِي الْبَابِ عَنْ عَائِشَةَ وَأُمِّ هَانِئٍ وَأَنَسٍ وَأُمِّ سَلَمَةَ وَابْنِ عَبَّاسٍ