In the name of allah, the Beneficent, the Merciful What is sin in Islam?

3. The Condition of Taking Allah's Name

The third Quranic condition is taking Allah's name at the time of killing an animal. This has been stated in different forms at different places in the Quran. Positively, it has been said:

Eat of that over which the Name of Allah has been mentioned if you are believers in His revelations.
And negatively:

And eat not of that whereon Allah's name has not been mentioned, for lo! It is abomination..
In hunting with trained animals, the following directions have been given:
(And those beasts and birds of prey, which you have trained, as hounds,... ) Eat of that which they catch for you and mention Allah's name upon it,' and observe your duty to Allah. Lo! Allah is swift to take account.
Then we see that, at several places, the Quran does not employ the word "slaughter" at all and, instead, uses "taking Allah's name" as a term.
That they may witness things that are of benefit to them, and mention the name of Allah on appointed days over the beast of cattle that He has bestowed upon them. (That is, they should slaughter them).
And for every nation We have appointed a slaughtering ritual, that they may mention the name of Allah over the beast of cattle that He has given them for food. (Again it means that they should slaughter the animals.)
So mention the name of Allah over them {the camels) when they are drawn up in lines. (That is, slaughter them.)
Eat of that over which the name of Allah has been mentioned. (That is, over which Allah's name is mentioned at the time of slaughtering it.)
And eat not of that over which Allah's name has not been mentioned. (That is, over which Allah's name is not mentioned at the time of slaughtering it.)
This repeated use of "taking Allah's name" for "slaughtering" conclusively proves that the two expressions are synonymous in the view of the Quran and that taking Allah's name is essential to the cleanness of the slaughtered animal.
We shall now inquire what legal position, according to the sound (saheeh) and firm (qawee) traditions of the Prophet, "taking Allah's name" has. Adi bin Hatim is the man who often questioned the Prophet about game hunting. The rules that the Prophet told him are as follows:
When you set off your dog mention Allah's name, and if it catches anything for you and you come up to it while it is still alive cut its throat; if you come up to it when the dog has killed it but not eaten any of it eat it; but if it has eaten any of it do not eat,... When you shoot an arrow mention Allah's name.
That which you have hunted with your bow and over which you have taken Allah's name you may eat; and that which you have hunted with your hound and over which you have taken Allah's name you may eat as well.
Spill blood with whatever instruments you chooses.
When you set off a trained dog or hawk, taking Allah's name as you set it off, you may eat of what it catches for you.
Adi bin Hatim asked the Prophet what to do in a situation when, having taken Allah's name, he sets off his dog and, on reaching the scene of hunt, sees another dog standing near by and finds it difficult to determine which of the two has killed the animal. The Prophet replied: "Don't eat, for you took Allah's name over your own dog and not over the other one."
These explicit and unmistakable injunctions of Allah and the Prophet leave no room for doubt that taking Allah's name is essential to the cleanness of the slaughtered animal and that the animal killed without Allah's name being taken over it is unclean. If verses and traditions as clear as these do not formulate any law, then one would like to know what kind of textual evidence (nuss) is required to formulate one.