Abu Dawud
Purification (Kitab Al-Taharah)
Book Number: 001 / Hadith Number: 8
Narated By Abu Hurairah : The Apostle of Allah (pbuh) said: "I am like a father to you. When any of you goes to the privy, he should not face or turn his back towards the qiblah. He should not cleanse with his right hand.