I asked Messenger of Allah ﷺ about looking hither and thither in prayer. He replied, "It is a way of stealing by which Satan takes away (a portion) from the prayer of a person." (Using translation from Bukhārī 751)   

سَأَلْتُ رَسُولَ اللهِ ﷺ عَنِ الِالْتِفَاتِ فِي الصَّلَاةِ قَالَ «اخْتِلَاسٌ يَخْتَلِسُهُ الشَّيْطَانُ مِنَ الصَّلَاةِ» خَالَفَهُ إِسْرَائِيلُ  

I asked Messenger of Allah ﷺ about looking hither and thither in prayer. He replied, "It is a way of stealing by which Satan takes away (a portion) from the prayer of a person." (Using translation from Bukhārī 751)  

سَأَلْتُ رَسُولَ اللهِ ﷺ عَنِ الِالْتِفَاتِ فِي الصَّلَاةِ قَالَ «هُوَ اخْتِلَاسٌ يَخْتَلِسُهُ الشَّيْطَانُ مِنْ صَلَاةِ الْعَبْدِ»  

"I heard Abu Al-Ahwas saying to us in a gathering with Ibn Al-Musayyab when Ibn Al-Musayyab was sitting there, that he had heard Abu Dharr say: The Messenger of Allah ﷺ said: "Allah (SWT) continues to look upon His slave while he is praying, so long as he does not turn away. If he turns his face away, He turns away from him." (Using translation from Nasāʾī 1195)   

قَالَ رَسُولُ اللهِ ﷺ «إِنَّ اللهَ مُقْبِلٌ عَلَى الْعَبْدِ فِي صَلَاتِهِ مَا لَمْ يَلْتَفِتْ فَإِذَا صَرْفَ وَجْهَهُ انْصَرَفَ عَنْهُ»