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." (Using translation from Nasāʾī 1117)
عَنْ رَسُولِ اللهِ ﷺ قَالَ «أَتِمُّوا الرُّكُوعَ وَالسُّجُودَ فَوَاللهِ إِنِّي لَأَرَاكُمْ خَلْفَ ظَهْرِي فِي رُكُوعِكُمْ وَسُجُودِكُمْ»
The Prophet ﷺ said, "Perform the bowing and the prostrations properly. By Allah, I see you from behind me (or from behind my back) when you bow or prostrate."
عَنِ النَّبِيِّ ﷺ قَالَ أَقِيمُوا الرُّكُوعَ وَالسُّجُودَ فَوَاللَّهِ إِنِّي لأَرَاكُمْ مِنْ بَعْدِي وَرُبَّمَا قَالَ مِنْ بَعْدِ ظَهْرِي إِذَا رَكَعْتُمْ وَسَجَدْتُمْ
Perform bowing and prostration well. By Allah, I see you even if you are behind me, or he said: (I see you) behind my back when you bow or prostrate.
عَنِ النَّبِيِّ ﷺ قَالَ أَقِيمُوا الرُّكُوعَ وَالسُّجُودَ فَوَاللَّهِ إِنِّي لأَرَاكُمْ مِنْ بَعْدِي وَرُبَّمَا قَالَ مِنْ بَعْدِ ظَهْرِي إِذَا رَكَعْتُمْ وَسَجَدْتُمْ
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."
عَنْ رَسُولِ اللَّهِ ﷺ قَالَ أَتِمُّوا الرُّكُوعَ وَالسُّجُودَ فَوَاللَّهِ إِنِّي لأَرَاكُمْ مِنْ خَلْفِ ظَهْرِي فِي رُكُوعِكُمْ وَسُجُودِكُمْ
The Prophet ﷺ said, "Perform the bowing and the prostrations properly. By Allah, I see you from behind me (or from behind my back) when you bow or prostrate." (Using translation from Bukhārī 742)
"أقيمُوا الرُّكوعَ والسُّجُود، فوالله إني لأراكُمْ مِن بعد ظَهْرِي إذا ركَعُتمْ وإذا سَجَدْتُمْ".