حَدَّثَنَا مُسْلِمُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَنَسٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ ‏"‏ اعْتَدِلُوا فِي السُّجُودِ وَلاَ يَفْتَرِشْ أَحَدُكُمْ ذِرَاعَيْهِ افْتِرَاشَ الْكَلْبِ ‏"‏ ‏.‏

Anas reported the Messenger of Allah(PBUH) as saying; Adopt a moderate position when prostrating yourselves, and see that none of you stretches out his forearms(on the ground) like a dog. Translation Not Available

Book Ref: Sunan Abi Dawud Book 2 Hadith 897
Web Ref:  Sunan Abi Dawud Book 2 Hadith 896