Christians think of Judaizing as a Christian defection, but the charge has been leveled by Muslims against one another.  Camilla Adang, for instance, has detailed how Ibn Hazm responded to what he thought were Jewish customs infiltrating the practices of Muslims in hte Malikite circle.  He denounces “Muslims who, despite the teaching that the Torah has been abrogated and distorted, revere it as a revealed scripture to the point of considering it as valid source from which to draw legal decisions.”  He worries about “coreligionists who to his mind adhere to certain practices associated with Judaism.”