Sunday, worship and rest
Sunday celebrates the Lord’s resurrection and gathers Christians for Eucharistic worship and a rhythm of rest. Catholic obligations include real distinctions for serious reasons, care duties, and legitimate dispensations. Rest serves persons, families, worship, and human freedom; it is not merely inactivity. Different Catholic calendars and local disciplines require attention before making universal claims about particular holy days.
Follow the sources
An original library introduction, with sources for further study. This is a starting point rather than a complete treatment or a finished formation lesson.