The Short Answer

The seven deuterocanonical books were part of the Greek Old Testament — the Septuagint — which was the Bible of the apostles, the early Church, and every major council that addressed the canon before the Protestant Reformation. They were quoted by the New Testament authors, cited by the Church Fathers, and affirmed by the Council of Carthage in 397 AD. Martin Luther removed them in the sixteenth century because they contradicted doctrines he had already decided to reject. The question is not why Catholics include them. The question is why Protestants removed them.

Which Books Are We Talking About?

The seven books present in Catholic and Orthodox Bibles but absent from Protestant ones are: Tobit, Judith, 1 Maccabees, 2 Maccabees, Wisdom (also called the Wisdom of Solomon), Sirach (also called Ecclesiasticus), and Baruch. Additionally, the Catholic versions of Daniel and Esther contain longer texts than the Protestant versions — passages preserved in the Greek Septuagint but not in the Hebrew Masoretic text.

These books were not written after the New Testament era. Most were composed between roughly 300 BC and 50 BC, making them ancient Jewish texts with direct relevance to the world into which Christ was born. Sirach, for example, is a profound wisdom text whose influence on the New Testament is widely acknowledged by scholars. First Maccabees is one of the most historically valuable documents of the Second Temple period.

The Septuagint: The Bible of the Apostles

When the New Testament authors quote the Old Testament — and they do so hundreds of times — they overwhelmingly quote the Septuagint, the Greek translation of the Hebrew scriptures produced in Alexandria beginning around 250 BC. The Septuagint was the standard biblical text in the Greek-speaking world of the first century, and it included the deuterocanonical books as part of the canon.

This is not a minor point. If the apostles consistently used a version of the Old Testament that included these seven books, it is at minimum misleading to claim that the apostolic Church considered them non-canonical. The apostles did not use a narrower Hebrew canon. They used the Septuagint.

The New Testament Uses These Books

The New Testament not only quotes the Septuagint — it draws specifically on the deuterocanonical books in ways that are difficult to explain if those books were considered non-authoritative.

The Letter to the Hebrews 11:35 references women who “received back their dead by resurrection” — a clear allusion to 2 Maccabees 7, the account of the martyred mother and her seven sons who accepted death trusting in resurrection. The Wisdom of Solomon deeply influenced the Christology of Paul and John: compare Wisdom 7:26 (“She is a reflection of eternal light”) with John 1:9 (“the true light that enlightens every man”). James 1:19 echoes Sirach 5:11. Matthew 6:14–15 parallels Sirach 28:2. The connections are pervasive.

The Early Church’s Canon

For the first fifteen centuries of Christianity, the deuterocanonical books were part of the accepted biblical canon throughout the Church. The Council of Rome (382 AD) under Pope Damasus I listed a canon that included them. The Council of Hippo (393 AD) and the Council of Carthage (397 and 419 AD) — the councils most influential in defining the Western canon — explicitly included them. St. Augustine, whose authority the Reformers frequently invoked on other matters, accepted the deuterocanonical books as canonical without reservation.

It was only in the sixteenth century, when Jerome’s preference for the Hebrew canon (known only from rabbinic Judaism after 90 AD) was revived and selectively applied, that serious doubt was cast on these books in the Western Church. Even Jerome, it should be noted, included them in his Vulgate translation and distinguished only between degrees of use, not between canonical and non-canonical in the modern Protestant sense.

Why Did the Reformers Remove Them?

The Protestant removal of the deuterocanonical books was not primarily a text-critical decision. It was a theological one. Luther rejected 2 Maccabees because it supports prayer for the dead and Purgatory — doctrines he had already repudiated. He rejected Sirach and Wisdom because they support the value of works in the moral life — a position in tension with his doctrine of justification by faith alone. The books were not removed because the evidence against their canonicity was compelling. They were removed because they were inconvenient.

This is not a charitable spin on the Reformers’ position — it is their own logic made explicit. Luther publicly called 2 Maccabees a book he would not use to establish doctrine precisely because of the passage on praying for the dead. The decision was theological before it was canonical.

The Catholic Response

Catholics did not add books to the Bible at the Council of Trent (1546). They reaffirmed the books that had been in the canon for over a thousand years. Trent defined dogmatically what the councils of Carthage and Hippo had already declared — and what the Fathers had already assumed. The dogmatic definition was a response to the Reformation’s subtraction, not a Catholic addition.

The question of the deuterocanonical books ultimately comes back to authority: who has the right to define the biblical canon? If it is the Church — as it must be, since Scripture cannot define its own limits — then the Church’s consistent, conciliar, patristic tradition of including these seven books should settle the question. If it is not the Church, then every individual believer must construct their own canon, and there is no principled stopping point.