Abdullah bin Abbas reported,

This verse was revealed while the Messenger of Allah ﷺ was in hiding in Mecca, "And do not raise your voice in your prayer, nor be too quiet in it" [Isra 17:110].He explained that when the Prophet led his companions in prayer, he would recite the Quran aloud. When the polytheists heard this, they would insult the Quran, the One who revealed it, and the one who brought it. So Allah said to His Prophet ﷺ, "And do not raise your voice in your prayer", meaning in your recitation, so that the polytheists hear it and insult the Quran, "nor be too quiet in it" from your companions, so that they cannot hear the Quran and learn it from you, "but seek a way between that" [Isra 17:110].

حدثنا هشيم أنبأنا أبو بشر عن سعيد بن جبير

عن ابن عباس قال

نزلت هذه الآية ورسول الله ﷺ متوار بمكة {ولا تجهر بصلاتك ولا تخافت بها} قال كان إذا صلى بأصحابه رفع صوته بالقرآن قال فلما سمع ذلك المشركون سبوا القرآن ومن أنزله ومن جاء به فقال الله عز وجل لنبيه ﷺ {ولا تجهر بصلاتك} أي بقراءتك فيسمع المشركون فيسبوا القرآن {ولا تخافت بها} عن أصحابك فلا تسمعهم القرآن حتى يأخذوه عنك {وابتغ بين ذلك سبيلا}