Sahih al-Bukhari 7490
Narrated Ibn `Abbas:
(regarding the Verse):-- 'Neither say your prayer aloud, nor say it in a low tone.' (17.110) This Verse 
was revealed while Allah's Messenger (ﷺ) was hiding himself in Mecca, and when he raised his voice while 
reciting the Qur'an, the pagans would hear him and abuse the Qur'an and its Revealer and to the one 
who brought it. So Allah said:-- 
'Neither say your prayer aloud, nor say it in a low tone.' (17.110) That is, 'Do not say your prayer so 
loudly that the pagans can hear you, nor say it in such a low tone that your companions do not hear 
you.' But seek a middle course between those (extremes), i.e., let your companions hear, but do not 
relate the Qur'an loudly, so that they may learn it from you.
حَدَّثَنَا مُسَدَّدٌ، عَنْ هُشَيْمٍ، عَنْ أَبِي بِشْرٍ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ ‏{‏وَلاَ تَجْهَرْ بِصَلاَتِكَ وَلاَ تُخَافِتْ بِهَا‏}‏ قَالَ أُنْزِلَتْ وَرَسُولُ اللَّهِ صلى الله عليه وسلم مُتَوَارٍ بِمَكَّةَ، فَكَانَ إِذَا رَفَعَ صَوْتَهُ سَمِعَ الْمُشْرِكُونَ فَسَبُّوا الْقُرْآنَ وَمَنْ أَنْزَلَهُ وَمَنْ جَاءَ بِهِ‏.‏ وَقَالَ اللَّهُ تَعَالَى ‏{‏وَلاَ تَجْهَرْ بِصَلاَتِكَ وَلاَ تُخَافِتْ بِهَا‏}‏ لاَ تَجْهَرْ بِصَلاَتِكَ حَتَّى يَسْمَعَ الْمُشْرِكُونَ، وَلاَ تُخَافِتْ بِهَا عَنْ أَصْحَابِكَ فَلاَ تُسْمِعُهُمْ ‏{‏وَابْتَغِ بَيْنَ ذَلِكَ سَبِيلاً‏}‏ أَسْمِعْهُمْ وَلاَ تَجْهَرْ حَتَّى يَأْخُذُوا عَنْكَ الْقُرْآنَ‏.‏