Book 2, Hadith 10

Yahya related to me from Malik from Safwan ibn Sulaym from Said ibn Salama of the Bani Azraq from al-Mughira ibn Abi Burda of the tribe of Bani Abd ad-Dar that he had heard Abu Hurayra speak about a man who came to the Messenger of Allah, may Allah bless him and grant him peace, and said, "Messenger of Allah! We travel by sea and we do not carry much fresh water with us so if we do wudu with it we go thirsty. Can we do wudu with seawater?" The Messenger of Allah, may Allah bless him and grant him peace, replied, "lts water is pure, and its dead creatures are halal