Abu Dawud Book 2, Hadith Number 1410.

Chapter : When should a person prostrate if he recites a quranic verse containing prostration.

Narated By Abdullah ibn Umar : Abu Tamimah al-Hujaymi said: When we came to Medina accompanying the caravan, I used to preach after the dawn prayer, and prostrate on account of the recitation of the Qur’an. Ibn Umar prohibited me three times, but I did not cease doing that. He then repeated (his prohibition) saying: I prayed behind the Apostle of Allah (PBUH), Abu Bakr, Umar and Uthman, they would not prostrate (on account of the recitation of the Qur’an) till the sun had risen.

Complete Translation of Sunan Abu-Dawud, Book 2: Prayer (Kitab Al-Salat): Detailed Injunctions about Witr