What is the Septuagint?

The Septuagint is an ancient Greek translation of the Old Testament, often abbreviated LXX. It became the Bible commonly used by Greek-speaking Jews and many early Christians.

Where it came from. Translation began in Alexandria, Egypt, around the third century BC, initially with the Torah, the first five books of the Bible. Other Old Testament books were translated over time. The name “Septuagint” comes from an ancient tradition that seventy or seventy-two Jewish scholars produced the translation. The historical details of that story are uncertain, but the translation itself is ancient and well attested.

Why it mattered. Greek was widely spoken throughout the eastern Mediterranean, while many Jews no longer understood Hebrew well. The Septuagint made the Scriptures accessible to them. It also provided much of the biblical vocabulary used by early Christians to proclaim Jesus. The New Testament was written in Greek, and many of its Old Testament quotations follow the Septuagint’s wording more closely than the later standardized Hebrew text.

Examples in the New Testament. Hebrews quotes Psalm 40 as saying, “a body you prepared for me” (Heb 10:5), following the Greek wording. Acts records Stephen saying that Jacob’s household numbered seventy-five persons when it entered Egypt (Acts 7:14), a number found in the Septuagint tradition. Matthew’s quotation, “the virgin shall be with child,” reflects the Septuagint translation of Isaiah 7:14 (Mt 1:23). These examples show that the apostles could use the Greek Old Testament as Scripture.

Its connection with the Catholic Bible. Ancient Septuagint manuscripts include books such as Wisdom, Sirach, Judith, Tobit, and Maccabees, although their exact contents and arrangement vary. The early Church received these deuterocanonical books as Scripture, and they remain part of the Catholic Old Testament. The Church’s canon contains forty-six Old Testament books and twenty-seven New Testament books (CCC 120). The Catholic canon rests on the Church’s apostolic Tradition and authoritative discernment, not simply on the contents of one surviving Septuagint manuscript.

How Catholics regard it. The Septuagint is not a separate revelation or a replacement for the Hebrew Scriptures. It is an ancient biblical textual tradition with immense importance for understanding the New Testament and the faith of the early Church. The Church honors both the Hebrew and Greek traditions when studying and translating Scripture.

When a New Testament quotation seems different from your Old Testament wording, check whether the author is quoting the Septuagint. That often explains the difference.