"Be moderate in bowing and prostration, and do not rest your forearms along the ground like a dog." (Using translation from Nasāʾī 1028)   

قَالَ رَسُولُ اللَّهِ ﷺ «اعْتَدِلُوا فِي الرُّكُوعِ وَالسُّجُودِ وَلَا يَبْسُطْ أَحَدُكُمْ ذِرَاعَيْهِ بِسَاطَ الْكَلْبِ»  

The Messenger of Allah ﷺ prohibited to peck like a crow, and to spread (the forearms) like a wild beast, and to fix a place in the mosque like a camel which fixes its place. These are the wordings of Qutaybah. (Using translation from Abū Dāʾūd 862)   

«نَهَى رَسُولُ اللَّهِ ﷺ عَنِ افْتِرَاشِ السَّبُعِ وَنَقْرَةِ الْغُرَابِ وَأَنْ يُوطِنَ الرَّجُلُ الْمَكَانَ كَمَا يُوطِنُ الْبَعِيرُ»