In the 1950s and 1960s three copies of portions of Sirach were found among the Dead Sea Scrolls. The largest scroll was discovered at Masada, the Jewish fortress destroyed in 73 CE. The earliest of these scrolls (2Q18) has been dated to the second part of the 1st century BCE, approximately 150 years after Sirach was first composed. These early Hebrew texts are in substantial agreement with the Hebrew texts discovered in Cairo, although there are numerous minor textual variants. With these findings, scholars are now more confident that the Cairo texts are reliable witnesses to the Hebrew original.
Although excluded from the Jewish canon, Sirach was read and quoted as authoritative from the beginning of the rabbinic period. There are numerous citations to Sirach in the Talmud and works of rabbinic literature (as “ספר בן סירא”, e.g., Hagigah 13a, Niddah 16b; Ber. 11b). Some of those (Sanhedrin 100b) record an unresolved debate between R’Joseph and Abaye as to whether it is forbidden to read the Sirach, wherein Abaye repeatedly draws parallels between statements in Sirach cited by R’Joseph as objectionable and similar statements appearing in canonical books.
Sirach may have been used as a basis for two important parts of the Jewish liturgy. In the Mahzor (High Holiday prayer book), a medieval Jewish poet may have used Sirach as the basis for a poem, KeOhel HaNimtah, in the Yom Kippur musaf (“additional”) service for the High Holidays. However, some question whether this passage in Sirach is referring at all to Yom Kippur, and thus argue it cannot form the basis of this poem. Some early 20th Century scholars also argued that the vocabulary and framework used by Sirach formed the basis of the most important of all Jewish prayers, the Amidah, but that conclusion is disputed as well.