Among those who forfeit their share in the world to come, the sages taught, is the one who reads sefarim chitzonim, "outside books." The phrase is a technical term. It refers to writings that circulated in Jewish communities but were never admitted into the canon of sacred Scripture. Once a book is declared outside, reading it for spiritual guidance is treated as a serious matter.
Rav Yosef in the Talmud singled out one work by name. "It is forbidden," he said, "to read the Book of the Son of Sira." Ben Sira, a Jewish teacher writing in Hebrew around 190 BCE in Jerusalem, had composed a long book of proverbs and ethical counsel. Much of it reads like the book of Proverbs itself. Some of it was beautiful and was even quoted approvingly by other rabbis. But the sages nevertheless kept it outside the canon.
Rav Yosef gave his reasons by quoting the passage that most troubled him. Ben Sira had written, "A daughter is a false treasure to her father. Because of anxiety for her he cannot sleep at night. When she is young, he fears she will be seduced. In her virginity, he fears she will play the harlot. When she is of marriageable age, he fears she will not find a husband" (Ecclesiasticus 42:9, as quoted in Sanhedrin 100b).
The rabbis did not object to every word Ben Sira wrote. They objected to the tone. A sacred book, in their reading, does not teach a father to treat his daughter as a cumbered inheritance. The canon was drawn not only around what was true, but around what was fit to be treated as Torah. Some works, however clever, teach a posture that the tradition refuses to bless.