The Book of Forgetfulness (In Prayer)
13/40. Chapter:
The prohibition of lifting one's gaze to the sky when supplicating during the prayer
Sunan an-Nasai
أَخْبَرَنَا أَحْمَدُ بْنُ عَمْرِو بْنِ السَّرْحِ، عَنِ ابْنِ وَهْبٍ، قَالَ أَخْبَرَنِي اللَّيْثُ، عَنْ جَعْفَرِ بْنِ رَبِيعَةَ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لَيَنْتَهِيَنَّ أَقْوَامٌ عَنْ رَفْعِ أَبْصَارِهِمْ عِنْدَ الدُّعَاءِ فِي الصَّلاَةِ إِلَى السَّمَاءِ أَوْ لَتُخْطَفَنَّ أَبْصَارُهُمْ " .
It was narrated from Abu Hurairah that: The Messenger of Allah (ﷺ) said: "People should certainly stop lifting their gaze to the sky when they supplicate during the prayer, or they will lose their eyesight."
Reference : Sunan an-Nasa'i 1276In-book reference : Book 13, Hadith 98English translation : Vol. 2, Book 13, Hadith 1277