(4) Prayer
كتاب الصلاة
(15a) Chapter: Prostration and its Excellence - Section 1
(14) باب السجود وفضله - الفصل الأول
Mishkat al-Masabih 888 
Anas reported God’s Messenger 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.” (Bukhari and Muslim.)
وَعَنْ أَنَسٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «اعْتَدِلُوا فِي السُّجُودِ وَلَا يَبْسُطْ أَحَدُكُمْ ذِرَاعَيْهِ انْبِسَاطَ الْكَلْبِ»
 مُتَّفَقٌ عَلَيْهِ  (الألباني)حكم :
Reference : Mishkat al-Masabih 888
In-book reference : Book 4, Hadith 312