Can you bring unshakable proof, that Saturday was really the 7th day of the week, that this is the day that G-d said is His Sabbath. And how can we prove that through time, we haven’t lost track and that our modern Saturdays are still the 7th day of the week?

Proof is a very interesting concept in philosophy. Karl Popper basically shows that you can never ‘prove’ anything, but only show that it is the most reasonable explanation. Therefore I can’t prove to you that Shabbat has always been on a Saturday, but I can give what I believe is the most reasonable explanation.

First we must accept that Moses received the Torah at Mount Sinai and gave it to the Jewish people (or we accept that when G-d gave the Ten Commandments He explained what he meant by the ‘Seventh Day’). That means that from that time onwards all (or at least a large percentage) of the Jewish people were observing Shabbat on Saturday. It is possible that some things get forgotten over time, but not something that happens once every seven days. In addition the penalties for breaking Shabbat were so big that any doubt as to which day it was would have been literally a question of life and death. People don’t forget things that are so important.

In addition, the days of the week have no names in Hebrew. They are only called ‘day one’, ‘day two’ etc. with Shabbat being the Seventh day, so there is no possibility of forgetting.

Finally, perhaps the most clear argument in favor of Shabbat always having been on Saturday is the fact that when Christianity was beginning, Paul had to explicitly change the day to Sunday, to distinguish between Jewish practice, and what was to become mainstream Christian practice (for this reason some Christian groups eg. Seventh Day Adventists still keep Sabbath on Saturday to revert to the original custom of the earliest Christians).

Yours,
Rabbi David Sedley