We are not allowed to wear a garment containing both wool and
linen. This forbidden mixture has a special name: shaatnez. The
reason for this mitzvah? Let’s start with a story. In Medieval
times, there was a legend of a creature called the vegetable
lamb. This myth sprung up as a way to explain the existence of
cotton, which was not indigenous to the Old World. When
travelers described wool that grew on a bush, the folks back
home envisioned sheep that grew from a plant. To our
sensibilities, isn’t such a hybrid creature nonsensical? Well,
that’s what shaatnez is. Wool comes from an animal and linen
comes from a plant. Mixing them together is tantamount to
second-guessing God by suggesting that His world is missing
something that He “should have” created. This is also why we
don’t crossbreed animals or graft different species of trees
together. Wearing shaatnez is as nonsensical in the spiritual
sense as the vegetable lamb is in the zoological sense. The
Rambam attributes the ban on shaatnez to an idolatrous