The Assyrian Church of the East observes Sunday (the Lord's Day) as the primary day of worship and celebration, commemorating the Resurrection of Christ. The church does not maintain Sabbatarian theology or practice, though the ancient Syriac Christian tradition has its own distinctive liturgical rhythm. The observance of Sunday as a day of worship and (ideally) Eucharistic celebration reflects the Apostolic practice and the early Christian understanding of Sunday as the Lord's Day on which he rose from the dead.

The church's liturgical practice does not impose Sabbath obligations or prohibit work on Saturday. The ancient Syriac tradition, while maintaining connection to Old Testament scriptural practice, understood the Incarnation and Resurrection as inaugurating a new era in which the ceremonial laws of the Old Testament are fulfilled and transformed in Christ. The church's focus is on the perpetual commemoration of Christ's redemptive work rather than on the observance of cyclical Sabbatarian practices.