[sevrinsky]

Try to think of the Torah -- God's literal word, to Orthodox Jews -- as the Constitution, and rabbinical scholars throughout the generations as the Supreme Court.

The Torah prohibits work on Shabbat, but only points out a few instances in the broadest terms. One of those is to not carry items "between domains", directly referenced in Exodus and Jerimiah, but again only a single passage in each instance. This was expanded upon in Talmudic works, which include an explanation of what exactly constitutes a public domain.

The eruv is not a loophole to "fool God". The eruv is a means to adjust the technical (or legal) definition of a public domain.

When one ensures that a community has a functioning eruv, that itself is part of Shabbat observance.