" أَتِمُّوا الرُّكُوعَ وَالسُّجُودَ فَوَاللَّهِ إِنِّي لأَرَاكُمْ مِنْ خَلْفِ ظَهْرِي فِي رُكُوعِكُمْ وَسُجُودِكُمْ "
It was narrated from Anas that: The Messenger of Allah (ﷺ) said: "Bow and prostrate properly, for by Allah (SWT) I can see you from behind my back when you bow and prostrate."