"The Messenger of Allah ﷺ said: 'If a man feels drowsy when he is praying, let him stop, lest he supplicate against himself without realizing.'" (Using translation from Nasāʾī 162)
قَالَ رَسُولُ اللهِ ﷺ «إِذَا نَعَسَ الرَّجُلُ وَهُوَ يُصَلِّي فَلْيَنْصَرِفْ لَعَلَّهُ يَدْعُو عَلَى نَفْسِهِ وَهُوَ لَا يَدْرِي»