And narrated Hamza bin 'Abdullah: My father said. "During the lifetime of Allah's Apostle, the dogs used to urinate, and pass through the mosques (come and go), nevertheless they never used to sprinkle water on it (urine of the dog.)"
Hadith ReferenceSahih Bukhari / The Book of Wudu (Ablution) / Hadith: 174
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة