This seemingly simple statement demonstrates Rabban Gamliel's brilliance. Even though the words Hasid and Am Ha'aretz have meant different things at different times, this statement remains true for all of the permutations of meaning throughout the ages.
The term of "Am Ha'aretz" in Tanach meant "ordinary Jew". In the time of the Talmud, this term meant "boor or ignoramus". Later, when modern nation of Israel was being resettled this term was used to mean "farmer or pioneer". Some years after that, this term was taken up by women (possibly under the influence of drugs) who wanted to follow in the tradition of Jezebel. Later still, after the advent of the internet, the term was picked up by bloggers trying to seem self-deprecating.
The earliest Hasidim were at the time of Matisyahu ben Yohanan. They are most famous for being slaughtered when they refused to fight on the Sabbath. Later Hasidim were described by Rabbi Yehudah he Hasid in this book Sefer Hasidim. They were were noted for their charity and generosity (it may be that he was the only one of this group, but some say his father was pretty nice too).
Later, the term Hasidim was applied to the people inspired by Yisroel ben Eliezer, the Ba'al Shem Tov. Later still, the term Hasidim was used to describe the imaginary people found in the books of Martin Buber, who bore little resemblance to any other Hasidim, living or deceased.
Application to the Mishnah
When Rabban Gamliel says וְלֹא עַם הָאָרֶץ חָסִיד this could mean:
- An ordinary Jew should not fail to defend himself on the Sabbath.
- An ordinary Jew cannot expect to be as charitable as Rabbi Yehudah.
- An ordinary Jew might try to follow the Ba'al Shem Tov, but most who thought that they were, actually were following their own ideas.
An ordinary Jew will not be found in Martin Buber's tales, since he specializes in unrealistic portrayals.
An boor will not fail to defend himself on the Sabbath (since he probably loves to fight anyway).
- An boor will not be as charitable as Rabbi Yehudah (although he might be the recipient of charity).
- An boor should not try to follow the Ba'al Shem Tov (although many did anyway).
An boor should not read Martin Buber's tales (since they will give him a misimpression of Hasidism).
An Israeli farmer will not fail to defend himself on the Sabbath (trust me, this one is for sure).
- An Israeli farmer should not be as generous as Rabbi Yehudah (or he and his family may lack things to eat).
- An Israeli farmer should not try to follow the Ba'al Shem Tov (he needs to concentrate on getting his crops in and not spend too much time away at his Rebbe's).
An Israeli farmer will not be found in Martin Buber's tales (since when they were written, the Second Aliyah was just beginning to take off).
A modern idolater will certainly defend herself on the Sabbath (since they they also worship themselves).
- A modern idolater will not usually be noted for their generosity.
- A modern idolater will most likely disparage the Ba'al Shem Tov and those he inspired.
A modern idolater will not be found in Martin Buber's tales; he might have been imaginative, but he wasn't debased.
A mouthy blogger will probably defend himself on the Sabbath (although it might be ineffective).
- A mouthy blogger may be expected to need more charity than they give.
- A mouthy blogger may like to hear about the Ba'al Shem Tov and other Rebbes, but follow them...?
- A mouthy blogger will not be found in Martin Buber's tales; even his fertile imagination could not come up with such a fantastical creature.
I hope this does some justice to Rabban Gamliel's great foresight. If, in the future, new definitions are applied to these terms, I have no doubt that his words would still be true.