Musnad Ahmad 30:3091

Muhammad ibn Ja'far narrated to us, he said: Shu'bah narrated to us, from Sulayman, from Dhakwan, from Abu Hurayrah, from the Prophet, may Allah bless him and grant him peace, that he said: "If the sandal strap of one of you breaks, let him not walk in one sandal." "And if a dog laps from the vessel of one of you, let him wash it seven times." Shu'bah said: Sulayman said: And Abu Razin narrated to me, he said: I heard Abu Hurayrah narrating it in this mosque while wearing two garments. I said to Shu'bah: "Like his hadith?" Shu'bah said: "I did not hear him say the like of it regarding the dog lapping in the vessel."