428. Ornamental: The prohibition against deriving benefit from the ornaments of idols
…do not desire the silver and gold on them to take for yourself… (Deuteronomy 7:25)
We are forbidden to have any benefit from the ornaments of an idol. This mitzvah applies even if we are still allowed to have benefit from the thing being worshipped. (How can we be permitted to have benefit from an idol, you ask? Not everything man has ever worshipped was built by man. Plenty of people have worshipped the sun but we never stopped using it! Nevertheless, ornaments used in such service are forbidden.)
The reason for this mitzvah is apparent: these objects are tainted by their association with idolatry, from which we are meant to distance ourselves. A special, separate mitzvah was given regarding the gold and silver used to decorate idols because people could easily be tempted into trying to take that for themselves, though it is still very much verboten.
This mitzvah applies in all times and places. It is discussed in the Talmud in tractate Avodah Zarah (45a-b). It is codified in the Shulchan Aruch in Yoreh Deah 145. This mitzvah is #22 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos and #17 of the 194 negative mitzvos that can be observed today as listed in the Chofetz Chaim’s Sefer HaMitzvos HaKatzar.