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."  

سَأَلْتُ رَسُولَ اللَّهِ ﷺ عَنْ الاِلْتِفَاتِ فِي الصَّلاَةِ فَقَالَ هُوَ اخْتِلاَسٌ يَخْتَلِسُهُ الشَّيْطَانُ مِنْ صَلاَةِ الْعَبْدِ  

"The Messenger of Allah said to me: 'O my son! Beware of looking around during the Salat, for indeed looking around during Salat is destruction. If you must do so, then in the voluntary (prayers), not in the obligatory (prayers).'" (Da'if)  

لِي رَسُولُ اللَّهِ ﷺ يَا بُنَىَّ إِيَّاكَ وَالاِلْتِفَاتَ فِي الصَّلاَةِ فَإِنَّ الاِلْتِفَاتَ فِي الصَّلاَةِ هَلَكَةٌ فَإِنْ كَانَ لاَ بُدَّ فَفِي التَّطَوُّعِ لاَ فِي الْفَرِيضَةِ