Nasai

It is understood that in the noble verse, the animal referred to is one that has died by itself and there was no opportunity to slaughter it. Similarly, any animal that is slaughtered in the name of anyone other than Allah is also forbidden (haram). Likewise, any animal slaughtered by a polytheist is also forbidden, whether he mentions the name of Allah or not, because he does not have faith in Allah. However, if a monotheist (muwahhid) forgets to mention the name of Allah at the time of slaughter, then by consensus his slaughtered animal is lawful (halal), because forgetfulness is an excuse. But if a monotheist deliberately does not mention the name of Allah at the time of slaughter, then according to most scholars, the slaughtered animal is forbidden (haram), because in this verse, it is prohibited to eat the animal over which the name of Allah has not been mentioned. However, Imam Shafi'i and some other scholars have declared such slaughtered animals to be lawful (halal), because the name of Allah remains established in the heart of the believer, whether he mentions it with his tongue or not. A mursal narration from Sunan Abu Dawud also conveys this meaning. According to them, the above verse: ﴿مِمَّا لَمْ يُذْكَرْ اسْمُ اللَّهِ عَلَيْهِ﴾ refers to a dead animal or an animal slaughtered in the name of other than Allah. And Allah knows best. However, the opinion of the majority of scholars is the preferred one.