Nearly 2,000 years ago, in the Mishnah, rabbis puzzled out 39 activities that constitute work and are forbidden on Shabbat.
He composed important treatises on Talmudic law and the Mishnah; many poems are also attributed to him on doubtful authority.
He lived from 150 to 210, and with his name is associated the compilation of the Mishnah.
His commentary on the Mishnah is the most useful of all helps to the understanding of that work.
But there are parts of the Mishnah which are older, and parts also at least a century later than the death of that great scholar.
This collection is the Mishnah; and the text as we have it now represents, in the main, the code of Rabbi.
The subject-matter of the Mishnah includes both law and morality, the affairs of the body, of the soul, and of the mind.
Mishnah itself became in turn the subject of further discussion.
The earliest occurrence of the term in the Mishnah, so far as I know, is at the end of chapter ix.
The Rebbe, of blessed memory, explains a bit of the Mishnah to him upside down.