The Prophet ﷺ said: When any of you prays, he should not place his sandals on his right side or on his left so as to be on the right side of someone else, unless no one is at his left, but should place them between his feet.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ إِذَا صَلَّى أَحَدُكُمْ فَلاَ يَضَعْ نَعْلَيْهِ عَنْ يَمِينِهِ وَلاَ عَنْ يَسَارِهِ فَتَكُونَ عَنْ يَمِينِ غَيْرِهِ إِلاَّ أَنْ لاَ يَكُونَ عَنْ يَسَارِهِ أَحَدٌ وَلْيَضَعْهُمَا بَيْنَ رِجْلَيْهِ  

when any of you prays and takes off his sandals, he should not harm anyone by them. He should place them between his feet or pray with them on  

عَنْ رَسُولِ اللَّهِ ﷺ قَالَ إِذَا صَلَّى أَحَدُكُمْ فَخَلَعَ نَعْلَيْهِ فَلاَ يُؤْذِ بِهِمَا أَحَدًا لِيَجْعَلْهُمَا بَيْنَ رِجْلَيْهِ أَوْ لِيُصَلِّ فِيهِمَا