Abstract Introduction Moral absolutism is the notion that “rights” and “wrongs” are independent of situational circumstances, and it is a core philosophy of many religious traditions. We tested whether active church members and Christian pastors showed resiliency to mild sleep restriction when reporting religious beliefs/cognitions, when logging spiritual behaviors, and when judging the deserved-punishments for moral mistakes. Methods We recruited 92 adults who identified as active in Christian churches (members and pastors). On a Monday, participants completed baseline religiosity, mood, and cognitive functioning measures and were then randomly assigned to adhere to early (10:30pm) or late (1:30am) bedtimes for four nights, with 7:30am waketimes, while wearing actigraphy and keeping a daily diary of spiritual behaviors. On Friday, participants repeated the baseline assessments, responded whether a series of biblical stories were literal versus figurative, and rated a series of vignettes about moral mistakes that were committed by in-group leaders (pastors) and out-group leaders (imams; vignettes counterbalanced). Results The late bedtime condition reduced actigraphy-defined sleep by 85 min/night (p<.001). Despite spending more time awake, this sleep restricted group reported engaging in fewer spiritual behaviors during the week (e.g., prayer time; p<.01). On Friday, the sleep restricted group had worse mood disturbances (p<.001), worse subjective sleepiness (p<.001), and altered perceptions of the meaning of the Garden of Eden and Noah’s ark biblical stories (p<.05). Fluid intelligence was unaffected (p=.78). When evaluating religious leaders who made moral mistakes, the sleep restricted participants were significantly less forgiving (p<.01); for example, well-rested participants thought such leaders were still “somewhat likely” to get into Heaven, but sleep-restricted participants rated the leaders as “not very likely” to get into Heaven (p<.01). The effects of sleep restriction were most prominent in participants who most frequently attended religious services and when rating out-group religious leaders (r = -.49; opposite patterns were noted when participants were well-rested). Conclusion In contrast to moral absolutism philosophies, very mild sleep restriction produced significant changes to religious cognitions (story interpretation), spiritual behaviors, and expressions of beliefs (likeliness of getting into Heaven), and expressions of virtues (decreased forgiveness). Support (if any) URSA Grant and National Science Foundation (1920730, 1943323).