It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "I am to you like a father. When any one of you goes to relieve himself, he should neither face the qiblah nor turn his back towards it, and he should cleanse himself with three stones. And he forbade dung and decayed bone, and also forbade cleansing oneself with the right hand."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 497