Sahih Al Bukhari Hadith Number 822

Narrated Anas bin Malik: The Prophet (peace be upon him) said, “Be straight in the prostrations and none of you should put his forearms on the ground (in the prostration) like a dog.”

10  Call to Prayers (Adhaan)
Hadith number 822
Volume no 1
Chapter: 141 (One should not put the forearms on the ground during prostrations)