Sahih Muslim Book 2, Hadith Number 576.

Chapter : Proof of the impurity of urine and that it is obligatory to safeguard oneself from it.

This hadith is transmitted from A’mash by Abmad b. Yusuf al-Azdi, Mu’alla b. Asad, Abd al-Wahid, Sulaiman with the same chain of transmitters but for the words: “The other did not keep himself safe from being defiled by urine.”