Gnosticism emerged in the 1st century from a mixture of Hellenistic ideas, Judaism, and early Christianity. A common thread of beliefs in Gnostic sects is that the material world is a prison created by a lesser god, the Demiurge, out of ignorance or malevolence, and that this prison keeps us from being with the supreme god. Many interpretations of Gnosticism viewed the Demiurge as Yahweh and held the creation of mankind as an imprisonment. When Adam and Eve ate the forbidden fruit in the Garden of Eden in this interpretation, they gained gnosis and mankind was able to achieve salvation from the Demiurge's prison. This obviously contradicts Jewish and Christian doctrine on this event and essentially villifies the Abrahamic God as the ultimate obstacle to the salvation of the souls of mankind.
Now let's assume that for whatever reason, a sect holding Gnostic beliefs on this matter becomes a dominant form of Christianity in a region. This could be as small as a single prosperous Roman province that forms an independent state or could be as large as the historic Christian world but in this state/states the ruling class and majority of the populace follows a Gnostic church and it is promoted as the state religion. We will assume this sect is broadly similar to some OTL Gnostic sect and it gained mass appeal like the Manichaeans or Cathars. This Gnostic church believe they are the true followers of Jesus and that other Christians are deluded and heretical. Yet what would their opinion be about the Jews? While other Christians at least acknowledge Jesus, the Jews vehemently follow the Abrahamic God (that is, the devil) to the point where they are believed to have killed Jesus.
One quote describes Gnosticism as "the greatest case of metaphysical anti-Semitism" so my first inclination is to think that these Gnostic Christians would consider Jews akin to how premodern Europe viewed literal devil worshippers and thus violently rooted out wherever they appear in this region? Or would pragmatic concerns of the authorities permit the development of a Jewish community under circumstances not much worse than OTL medieval Europe (i.e. restrictions on daily life with occasional severe persecutions and expulsions)? I understand that Gnostic sects varied in their doctrines on the Demiurge and his identification, but I assume that some view of the Jews as devil worshippers would be more prevalent, influential, and shocking than comparable Christian doctrines that have inspired antisemitism.
Now let's assume that for whatever reason, a sect holding Gnostic beliefs on this matter becomes a dominant form of Christianity in a region. This could be as small as a single prosperous Roman province that forms an independent state or could be as large as the historic Christian world but in this state/states the ruling class and majority of the populace follows a Gnostic church and it is promoted as the state religion. We will assume this sect is broadly similar to some OTL Gnostic sect and it gained mass appeal like the Manichaeans or Cathars. This Gnostic church believe they are the true followers of Jesus and that other Christians are deluded and heretical. Yet what would their opinion be about the Jews? While other Christians at least acknowledge Jesus, the Jews vehemently follow the Abrahamic God (that is, the devil) to the point where they are believed to have killed Jesus.
One quote describes Gnosticism as "the greatest case of metaphysical anti-Semitism" so my first inclination is to think that these Gnostic Christians would consider Jews akin to how premodern Europe viewed literal devil worshippers and thus violently rooted out wherever they appear in this region? Or would pragmatic concerns of the authorities permit the development of a Jewish community under circumstances not much worse than OTL medieval Europe (i.e. restrictions on daily life with occasional severe persecutions and expulsions)? I understand that Gnostic sects varied in their doctrines on the Demiurge and his identification, but I assume that some view of the Jews as devil worshippers would be more prevalent, influential, and shocking than comparable Christian doctrines that have inspired antisemitism.