The purpose of this insightful study is to provide a model for explaining how intrinsic religiosity influences ethical decision-making in the business. The quantitative research collection was systematically searched and chosen based on specific criteria. Then, by analyzing and combining these researches, it was shown that intrinsic religiosity has a positive effect on ethical decision-making both directly and through the strengthening of variables such as homogeneity and the sense of guilt caused by immoral behavior and the weakening of the variable of Machiavellian morality. Approximately 80% of quantitative researches has reported this positive and significant impact, and it is considered stronger in consumers rather than top managers and experts and weaker in narcissistic personalities, rich people, malignant and active people in ethical issues. Finally, more research is suggested by longitudinal/ experimental/ interventional approaches. More consideration in non-Christian religions is suggested and variables such as love for money, commitment to moral improvement and perceived moral perception, as mediators, and variables such as type of occupation, degree of recognition, type of organization, social pressure for religiosity, cognitive abilities and the creation of opportunities for immoral behavior are also suggested to be used as moderators.