كتاب الطهارة
Read the English translation first, with the original Arabic directly underneath.
Narrated Abu Hurairah:
The Prophet (sal Allaahu alayhi wa sallam) said: The purification of the utensil belonging to any one of you, after it has been licked by a dog, consists of washing it seven times, using sand in the first instance. Abu Dawud said : A similar tradition has been narrated by Abu Ayyub and Habib b. al-Shahid on the authority of Muhammad.
طُهُورُ إِنَاءِ أَحَدِكُمْ إِذَا وَلَغَ فِيهِ الْكَلْبُ أَنْ يُغْسَلَ سَبْعَ مِرَارٍ أُولاَهُنَّ بِتُرَابٍ