مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 888
Prayer
Prostration and its Excellence - Section 1
وَعَنْ أَنَسٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «اعْتَدِلُوا فِي السُّجُودِ وَلَا يَبْسُطْ أَحَدُكُمْ ذِرَاعَيْهِ انْبِسَاطَ الْكَلْبِ»
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.)
Mishkat al-Masabih, 888مُتَّفَقٌ عَلَيْهِ (الألباني)