Chapter 84:11-12
Laws of Carrying: Clothing & Jewelry
11. It is permissible to lift up the edges of one's garments slightly so
they do not become soiled when passing through a dirty or muddy area. It
is, however, forbidden to lift them up entirely [since this would be
considered carrying] (1).
12. It is permissible to go out [into the public domain] on Shabbos
wearing two garments, one on top of the other, even if one is not wearing
the second garment for one's own purposes, but in order to [bring it to] a
friend or the like.
[This leniency is granted] only when, during the week, one might go out
wearing two garments of this nature (although usually one doesn't), since
then [wearing the second piece of clothing] can be considered a normal way
of dressing. If, however, one never wears two garments of this nature, it
is forbidden to wear the second garment, because it is viewed like a
"masui" (an object being carried rather than worn) (2).
The same principles apply to wearing two pairs of socks or wearing a large
hat over a small cap (such as a "yarmulka," ("skull cap") ).
FOOTNOTES:
(1) See Mishna Berura 301:117.
(2) According to the Mishna Berura (301:133), even wearing two garments in
a way that one would never usually wear them, is still only a violation of
a rabbinical decree. In other words, once one is wearing an item, rather
than carrying it, it is no longer a biblical violation, however the Rabbis
prohibited wearing something in a way one would never wear it, because then
it is obvious to others that one is trying to transport an object to a
friend, rather than wear it for one's own benefit.