Undesirability of Glancing in one Direction of the other during Prayer

Imam Al-Nawawi’s Riyad-us-Saliheen
Chapter 341
Undesirability of Glancing in one Direction of the other during Prayer

1755. `Aishah (May Allah be pleased with her) said: I asked the Messenger of Allah (sallallaahu ’alayhi wa sallam) about random looks in Salat (prayer), and he replied, “It is something which Satan snatches from the slave’s Salat.
[Al-Bukhari].

1756.  Anas (May Allah be pleased with him) said: The Messenger of Allah (sallallaahu ’alayhi wa sallam) said to me, “Beware of looking around in Salat (prayer), because random looks in Salat are a cause of destruction. If there should be no help from it, it is permissible in the voluntary and not in obligatory Salat.”
[At-Tirmidhi].