Hadith 1755
'Aishah (May Allah be pleased with her) said:
عن عائشة رضي الله عنها قالت: سألت رسول الله صلى الله عليه وسلم عن الالتفات في الصلاة فقال: "هو اختلاس يختلسه الشيطان من صلاة العبد" ((رواه البخاري)).
I asked the Messenger of Allah (ﷺ) about random looks in Salat (prayer), and he replied, "It is something which Satan snatches from the slave's Salat." [Al-Bukhari].
In plain words
Aishah asked about glancing around in prayer, and the Prophet said it is something Satan steals from a worshipper's Salat. Stray looks quietly rob us of the focus prayer deserves.
Reference : Riyad as-Salihin 1755 In-book reference : Book 17, Hadith 245