What is the ruling on omitting the basmalah when slaughtering, and is it obligatory for the basmalah to be complete?

The questioner : What is the ruling for one who omits the basmalah when slaughtering an animal, and is it obligatory for it to be complete? Please inform us of this, may Allah reward you.

The Shaykh : One who omits the mention of Allah’s name when slaughtering is in one of two states: either he omits it due to an excuse such as ignorance or forgetfulness, or he omits it without an excuse. If he omits it without an excuse, then the slaughtered animal is not lawful, because he has left out a condition for the lawfulness of the slaughter. The Prophet (peace and blessings be upon him) said: , so the Prophet (peace and blessings be upon him) made the mention of Allah’s name a condition for the lawfulness of the slaughter. And Allah the Exalted said: . As for when he omits it while excused by ignorance or forgetfulness, the majority of the scholars hold that the slaughtered animal is lawful because he is excused. And Allah the Exalted said: , so Allah the Exalted said: .
Some of the scholars from the Salaf and the Khalaf held that the slaughtered animal is not lawful even if the person is excused by ignorance or forgetfulness. Thus, if one slaughters an animal and forgets to mention Allah, the animal is not lawful. Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him) chose this opinion, and it is the stronger position that eating anything upon which Allah’s name has not been mentioned is forbidden. This is based on the saying of Allah the Exalted: The one who slaughters and forgets to mention Allah’s name on the animal does not commit a sin, because he is excused. As for the eater, it is not lawful for him to eat from that upon which Allah’s name has not been mentioned. However, if he forgets and eats, he does not commit a sin because he is excused. We must know the difference between these two aspects and say: We acknowledge that Allah the Exalted does not hold people accountable for ignorance and forgetfulness. But here there are two actions: the action of the slaughterer is not held accountable for due to ignorance and forgetfulness, and he is not punished for it. And the action of the eater, if he intentionally eats from something upon which Allah’s name has not been mentioned, and Allah has forbidden it, then he has fallen into sin. Then, the saying of the Prophet (peace and blessings be upon him): is evidence that mentioning Allah’s name on the slaughtered animal is like letting its blood flow, and both are conditions. A condition is not dropped by ignorance or forgetfulness. If a person was ignorant and slaughtered the animal in a way that does not let the blood flow, but he was ignorant, it is known that this slaughter of his is not eaten, because it falls under the strangled animal and the like, which Allah the Mighty and Majestic forbade in His saying: and so on. And if he forgot to slaughter it in a way that lets the blood flow and killed it with something that does not let the blood flow, it is not lawful, even if this man was forgetful. But this killer does not commit a sin by his forgetfulness, because it is forgiven for him. So likewise, if he forgot to mention Allah or was ignorant of mentioning Allah, because both are in one hadith and their outcome is the same. Therefore, it is not lawful for anyone to eat a slaughtered animal upon which Allah’s name has not been mentioned, even if the omission of the mention was due to forgetfulness.
For this reason, if a person prayed without ablution while forgetful, his prayer would be invalid and he would have to repeat it, even though he is not held accountable for his prayer without ablution because he was forgetful. But his not being held accountable for praying without ablution while forgetful does not mean that he is not required to repeat it.
Someone might say: There is a waste of wealth in forbidding it, meaning: forbidding the slaughtered animal upon which Allah’s name was not mentioned due to forgetfulness. We say: There is no waste of wealth in that, but rather it is a protection for the person so that he does not eat from that upon which Allah’s name has not been mentioned. Because if we tell this man who forgot to mention the name that his slaughter is now forbidden, that will lead him to remember the mention in the future and never forget it. Unlike if we say that it is forgiven and that eating this slaughtered animal is lawful; if he knows that the matter is easy, he might be negligent in remembering the mention.
This matter has been elaborated upon in other places.
And as for the sayingThe questioner : Does the mention need to be completed or not?
The apparent meaning of the texts is that it is not completed, and that it is sufficient to say “In the name of Allah” only.