Romans 14:5 and Sacred Days
Romans 14:5 does not name the Sabbath. Paul says that one person esteems one day above another while another esteems every day alike, and that each should be persuaded before God.
The Broad Liberty Reading
The strongest competing reading takes Paul's words at their ordinary breadth. The chapter addresses disputed practices among Christians, and verse 5 grants liberty regarding sacred days generally. On that reading, no Christian may make Sabbath observance a condition of fellowship or salvation.
The Fasting and Devotional-Day Reading
Verse 6 joins observing a day with eating and not eating. Because the chapter repeatedly discusses food, some interpreters understand the disputed days as fasting or devotional choices rather than the weekly Sabbath. This book favors that reading and treats the Decalogue as outside Paul's list of disputable practices.
Paul never labels the days as fast days, however. The connection to fasting is an inference from context, just as the broad application to every sacred day is an inference from the verse's general wording.
What the Text Settles
Paul commands conviction before God, gratitude, and refusal to despise or judge another servant. The passage does not establish Sunday, describe a transfer from the seventh day, or explicitly repeal the Fourth Commandment.
This book argues for continued Sabbath obligation from the commandment and the larger biblical pattern. A reader who adopts the broad liberty reading will disagree at precisely this point. The disagreement should be stated rather than hidden by calling Romans 14 only a fasting passage.