Sunan at-Tirmithiy كتاب الطهارة باب ما جاء فى سؤر الكلب
The Prophet, peace and blessings of God be upon him, said, "A vessel is washed seven times if a dog laps water from it; the first or last of them with dust. The vessel is washed once, if a cat laps water from it." Click on ḥadīth to read more