Ibn Abbas Narrated that: The Messenger of Allah recited "Verily Allah intends to keep off from you every kind of uncleanness O' People of the House (Ahlul-Bayt), and purify you a perfect purification". (Quran, the last sentence of Verse 33:33) and then the Messenger of Allah said: "Thus Me and my Ahlul-Bayt are clear from the sins."
Sunni reference: Sahih al-Tirmidhi, as quoted in: al-Durr al-Manthoor, by Jalaluddin al-Suyuti, v5, pp 605-606,198 under the commentary of Verse 33:33 of Quran Dala'il al-Nabawiyyah, by al-Bayhaqi
"It is this and nothing else that Allah willed to ward off every badness and indecency from the people of the family of Muhammad and to keep them clear from every contamination and sin!"
Sunni reference: Tafsir al-Tabari, v22, p5 under commentary of verse 33:33