كتاب الصلاة
2  
The Book of Prayer
Narrated 'Aishah (RA):
I asked Allah's Messenger (ﷺ) about looking around during prayer and he said, "It is something which the devil snatches from a person's prayer." [Reported by al-Bukhari].
عَنْ عَائِشَةَ ‏-‏-رَضِيَ اَللَّهُ عَنْهَا‏-‏- قَالَتْ : { سَأَلْتُ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-عَنْ اَلِالْتِفَاتِ فِي اَلصَّلَاةِ ? فَقَالَ : "هُوَ اِخْتِلَاسٌ يَخْتَلِسُهُ اَلشَّيْطَانُ مِنْ صَلَاةِ اَلْعَبْدِ } رَوَاهُ اَلْبُخَارِيُّ .‏ 1


‏1 ‏- صحيح .‏ رواه البخاري (751)‏ .‏

Sunnah.com reference : Book 2, Hadith 112
English translation : Book 2, Hadith 241
Arabic reference : Book 2, Hadith 243