Surah Al-An'am — Ayah 121 (6:121)
وَلَا تَأۡكُلُواْ مِمَّا لَمۡ يُذۡكَرِ ٱسۡمُ ٱللَّهِ عَلَيۡهِ وَإِنَّهُۥ لَفِسۡقٞۗ وَإِنَّ ٱلشَّيَٰطِينَ لَيُوحُونَ إِلَىٰٓ أَوۡلِيَآئِهِمۡ لِيُجَٰدِلُوكُمۡۖ وَإِنۡ أَطَعۡتُمُوهُمۡ إِنَّكُمۡ لَمُشۡرِكُونَ ١٢١
English translation (Saheeh International)
And do not eat of that upon which the name of Allāh has not been mentioned, for indeed, it is grave disobedience. And indeed do the devils inspire their allies [among men] to dispute with you. And if you were to obey them, indeed, you would be associators [of others with Him].1
- - i.e., by your obedience to them - obedience being the basis of worship.
Brief commentary
O Muslims, do not eat that which was not slaughtered in the name of Allah, whether the name of someone other than Allah was mentioned over it or not. Eating such forbidden food is to abandon obedience to Allah in favour of disobedience. The satans whisper to their friends, inspiring them with doubts, so that they argue with you about eating carrion. If you, O Muslims, were to follow them in the doubts they present for the lawfulness of carrion, then you would be equal to them in associating partners with Allah.