(12) Did the sabbath command exist prior to it being given to Moses? If so, how do you respond to Nehemiah 9:14 which says it was made known to Moses?

Thank you for your question.

We have a couple of articles on the site created specifically for a question like this one. Please see:

-Sabbath in Genesis
-Who kept the Sabbath

It should be noted that its existence as far back as Exodus 16 at least tells us it existed before it was given within the 10 Commandments. But if you want to see its existence farther back, the above article provides adequate proof.

As for the verse in question:

Nehemiah 9:14
And madest known unto them thy holy sabbath and commandedst them precepts, statutes, and laws, by the hand of Moses thy servant:

Note it says he "made it KNOWN" and not "he created it for the first time with" or "he gave it only to..." or "he gave it for the first time" etc. We should notice both what a verse says and what it does not say. As an example, my wife made KNOWN to me that she had a birth mark under her right foot after we got married. Does that mean her birth mark did not exist before she "madest it known" unto me? Of course not. It's been there since her birth. In other words, just because the Sabbath was "made known" unto the Israelites, does not mean it didn't exist prior.

I hope this helps.

In Jesus, the Solution,
Edwin M. Cotto