This volume collects papers presented at the Tenth International Symposium of the Leuven Centre for the Study of the Gospels, held in July 2022. As the title suggests, the purpose of the conference was to bring together experts on the literature of early Christianity to study how these texts theorize and negotiate difference within groups, polemicize and express enmity against opponents (real or imagined), and engage in competition with other groups, movements, or even texts. Rather than limit contributions to gospel literature, the organizers decided to expand the scope to include other early Christian texts, allowing for a broader array of studies. The title also signals the crucial question which all these papers address in one way or another, which is: at what point does diversity (of belief, practice, or association) cease to be acceptable and begin to be constructed as unacceptable difference, or even deviance?