Religious schools in Spain and Italy have been focused for centuries on spreading the Bible's message among students. In the beginning of the sacred scriptures, there is a mandate to protect nature as God's steward of creation; however, that reality has played a secondary role amongst believers and educational institutions. 180 Spanish and 135 Italian religious schools participated in the study. Through structural equation modeling (SEM-PLS), hypotheses were defined based on the understanding of sustainability as a moral issue. Results underscored that religious schools should protect nature by combining religion and environmental science.