In the Mishna (90a) we find that Rabbi Akiva includes people who read sefarim ḥitzoni’im – books outside the Biblical canon – among those who do not have a share in the World-to-Come. The Gemara on today’s daf offers a baraita that defines these books as sifrei minim – books of heretics – while Rav Yosef teaches that it also includes Sefer ben Sira.
Sefer ben Sira is one of the earliest books composed after the closing of the Biblical canon. It was authored by Yehoshua ben Sira, a native of Jerusalem, who was a younger contemporary of Shimon HaTzaddik, prior to the Hasmonean era. The book of ben Sira was held in great esteem, and after its translation into Greek by the author’s grandson (in the year 132 BCE in Alexandria ), it because widely known even among those who were not familiar with the Hebrew language. Sefer ben Sira is included as a canonical work in the Septuagint (and therefore is considered such in many other translations of the Bible), and although the Sages chose to view it as one of the sefarim ḥitzoni’im – books outside of the canon – they quote it in a respectful manner throughout the Talmud, sometimes even referring to it as ketuvim. Still, because of confusion between this work and another one that was known as Alfa-Beta d’Ben-Sira, which was a popular – and problematic – work, we find statements in the Gemara forbidding the study of Sefer ben Sira.
For generations Sefer ben Sira was known only from its translations, but recently parts of it have been found in the original Hebrew (in Masada and elsewhere). Since it was not part of the official Biblical canon it appears that the copyists felt more freedom when working with it and we find several different versions of the same text. When it appears in the Talmud it seems likely that it is being quoted by heart by the Sages, rather than from a written text.