The Book of Forgetfulness (In Prayer)
13/11. Chapter:
Concession allowing one to turn to the right or left when praying
Sunan an-Nasai
أَخْبَرَنَا أَبُو عَمَّارٍ الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ حَدَّثَنَا الْفَضْلُ بْنُ مُوسَى، عَنْ عَبْدِ اللَّهِ بْنِ سَعِيدِ بْنِ أَبِي هِنْدٍ، عَنْ ثَوْرِ بْنِ زَيْدٍ، عَنْ عِكْرِمَةَ، عَنِ ابْنِ عَبَّاسٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَلْتَفِتُ فِي صَلاَتِهِ يَمِينًا وَشِمَالاً وَلاَ يَلْوِي عُنُقَهُ خَلْفَ ظَهْرِهِ .
It was narrated that Ibn 'Abbas said: "The Messenger of Allah (ﷺ) used to turn to his right and left when praying, but he did not twist his neck to look behind him."
Reference : Sunan an-Nasa'i 1201In-book reference : Book 13, Hadith 23English translation : Vol. 2, Book 13, Hadith 1202