حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا يَحْيَى بْنُ زَكَرِيَّاءَ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، فِي قَوْلِهِ عَزَّ وَجَلَّ ‏ End hadith 7‏ قَالَتْ أُنْزِلَ هَذَا فِي الدُّعَاءِ ‏.‏

'A'isha reported that so far as these words of (Allah) Glorious and High are concerned: " And utter not thy prayer loudly, not be low in it" (xvii. 110) relate to supplication (du'a'). Translation Not Available

Book Ref: Sahih Muslim Book 4 Hadith 898
Web Ref:  Sahih Muslim Book 4 Hadith 447 a