A person conscientiously believing that the 7th day of the week ought to be observed as the Sabbath, and actually refraining from secular business and labor on that day, is not liable for penalties under this subchapter for doing such business or labor on the first day of the week, if the person does not disturb other persons.   [RR 2025, c. 2, Pt. E, §25 (COR).]