Sahih Muslim Book 21, Hadith Number 4742.

Chapter : Hunting with the help of trained dogs.

‘Adi b. Hatim reported: I asked Allah’s Messenger (may peace be upon him) about hunting. He said: When you shoot your arrow, recite the name of Allah, and if you find it (the arrow) killed (that), then eat, except when you find it fallen into water, for in that case you do not know whether it is water that caused its death or your arrow.