Question: "What is the book of Sirach?"
Answer: The book of Sirach is part of what is considered the Apocrypha/Deuterocanonical scripture and appears in the Old Testament of Catholic Bible. It is considered one of the “wisdom” books. Except for some Episcopal or Lutheran Bibles, Sirach and other books of the Apocrypha do not appear in Protestant Bibles. Apocrypha means “hidden,” and deuterocanonical means “second-listed.” Books of the Apocrypha were generally written in the roughly 400 years between the composition of the books in the Old and New Testaments, the intertestamental period. Sirach, also known as "Eccelesiasticus" or the "Wisdom of Sirach," is one of 12–15 books generally recognized as comprising the Apocrypha.
Controversy surrounds the Apocrypha regarding whether these books are from God and divinely inspired. For example, some biblical scholars point out that Jesus never quoted any verses from the Apocrypha, although He quoted with great frequency from many Old Testament books. Many books of the Apocrypha contain historical or geographical inaccuracies and teach false doctrines (e.g., the book of Tobit claims good works lead to salvation). Plus, Jewish Scripture never included any of these documents as sacred writings.
Jesus, son of Eleazar, son of Sirach, is believed to have written this book between 200–175 BC. The book of Sirach possesses a wealth of varied expressions of wise and foolish behavior reminiscent of the book of Proverbs. Many of its verses have Old Testament antecedents, especially from the book of Proverbs (dozens of related verses) and the Pentateuch, which is comprised of the first five books of the Bible. Portions of Sirach are used today in Catholic Church liturgy.
While most of this book tracks with long-standing, sound biblical doctrine, there are several tenets that conflict significantly with Christian beliefs. In several places, Sirach implies our actions can bring favor upon ourselves, mitigate our sin in God’s eyes, and anticipate reciprocal responses from those we assist in their time of need (chapters 3, 7, 12, 17, and 22). This is in stark contrast to the Bible’s teaching to be a cheerful giver (2 Corinthians 9:7), salvation through faith and not by works (Ephesians 2:8-9), and Jesus’ exhortation to give without expecting anything in return (Matthew 6:3).
Providing readers precise Sirach citations (chapter and verse, as with the Bible) is highly problematic, as a firm numbering construct apparently does not exist. For example, in the New American Bible (Catholic Bible Press, 1987) and the Apocrypha (God’s Word Translation, Baker Books, 2009), there are several instances where the numbering of verses as well as total number of chapter verses differ. As a result, only Sirach chapters are referenced above.
The book of Sirach is not part of the recognized canon of Scripture, and it is not the inspired Word of God. As such, although it may have some historical/cultural significance, it is not God-breathed and does not possess the qualities of divinely inspired Scripture (2 Timothy 3:16).