What is the instruction given by Prophet Muhammad (saw) regarding the slaughtering of animals?
 Narrated Abaya bin Rifaa:                     My grandfather, Rafi` bin Khadij said, "We were in the valley of Dhul-Hulaifa of Tuhama in the company of the Prophet and had some camels and sheep (of the booty). The people hurried (in slaughtering the animals) and put their meat in the pots and started cooking. Allah's Apostle came and ordered them to upset the pots, and distributed the booty considering one camel as equal to ten sheep. One of the camels fled and the people had only a few horses, so they got worried. (The camel was chased and) a man slopped the camel by throwing an arrow at it. Allah's Apostle said, 'Some of these animals are untamed like wild animals, so if anyone of them went out of your control, then you should treat it as you have done now.' " My grandfather said, "O Allah's Apostle! We fear that we may meet our enemy tomorrow and we have no knives, could we slaughter the animals with reeds?" The Prophet said, "Yes, or you can use what would make blood flow (slaughter) and you can eat what is slaughtered and the Name of Allah is mentioned at the time of slaughtering. But don't use teeth or fingernails (in slaughtering). I will tell you why, as for teeth, they are bones, and fingernails are used by Ethiopians for slaughtering. (See Hadith 668)