عَنْ عَبْدِ الرَّحْمَنِ بْنِ شِبْلٍ قَالَ: نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَن نَقْرَةِ الْغُرَابِ وَافْتِرَاشِ السَّبُعِ وَأَنْ يُوَطِّنَ الرَّجُلُ الْمَكَانَ فِي الْمَسْجِدِ كَمَا يُوَطِّنُ الْبَعِيرُ. رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ والدارمي

Talq b. ‘Ali al-Hanafi reported God’s Messenger as saying, “God does not regard the prayer of a servant who does not straighten his spine between his bowing and his prostration.” Ahmad transmitted it.