Before us is a Mishnah in Maseches Shabbos dealing with the law of drying oneself with a towel on Shabbos, and the question of whether there is a concern that one might wring out the towel.
"Mi sherochetz b'mei me'arah uv'chamei Teveryah" - one who bathes in cave water or in the hot springs of Tiberias:
The Gemara explains that the Mishnah mentioned cave water in order to teach us that it too is hot, like the hot springs of Tiberias. These are waters that were heated before Shabbos, and even so they are an exception to the rule, since it is permitted to bathe in them on Shabbos even though they are hot.
Why the Mishnah uses the language of bedieved (after the fact):
The Mishnah uses the language of bedieved - "mi sherochetz" - one who bathes - as if to say that only after the fact, if he went and bathed in them, do the laws that follow apply, and not that he is permitted to bathe in them at the outset. The reason: the hot springs of Tiberias are an exception and one may bathe in them, yet there is nothing here beyond a rabbinic decree. For this reason the Mishnah phrased it as "if you bathed in them" - and from that point on the law brought below applies.
"V'hisnageiv b'magevet" - and he dried himself with a towel:
Here the Mishnah distinguishes between an individual drying himself with many towels and many people drying themselves with a single towel:
An individual who dries himself with ten towels: Even if he used ten towels, and each one of them became only minimally wet, he may not carry them home in his hand - and this is so even in a place that has an eruv, where there is no concern of carrying. The reason: it is a decree lest he come to wring out the towel, and even though the multitude of towels makes the concern quite remote, the Sages did not distinguish in their decree between one towel and many towels, and in any case he may not carry them home.
Ten people who dry themselves with a single towel: They bathe and dry their faces, hands and feet with it, and they bring it home with them. Even though the towel is very wet because of the number of people using it, there is no concern here, since many people tend to remind one another not to desecrate Shabbos. This is not so with an individual, for even though he has several towels in his hand, there is no one to remind him - and therefore the concern exists.
The halachah: In practice, it emerges from the Gemara that the halachah does not follow our Mishnah; rather, even an individual may carry with him the towel he dried himself with on Shabbos, and we do not suspect that he will come to wring it out.
In summary: In this Mishnah we learned the law of one who bathes in cave water and in the hot springs of Tiberias, which were heated before Shabbos and in which it is permitted to bathe; the language of bedieved that the Mishnah employed; and the distinction between an individual drying himself with ten towels, who may not carry them in his hand because of the decree against wringing, and ten people drying themselves with a single towel, who do bring it with them because many people remind one another. And in practice the ruling is not like our Mishnah, and even an individual may carry his towel with him.