The Book of Tobit is one of the seven deuterocanonical books of the Old Testament. The Church accepted it into the canon despite some resistance because the Jews themselves had not accepted it as part of their scriptures. The reasons emerged over time. The Deuterocanonical books present originality in relation to the Torah because they have an orientation toward innovation that emerged from the Jewish heritage of Scripture. They give fulfillment to the revelation of the Hebrew Scriptures while at the same time opening to a beyond, to the mystery that is a precious heritage for us today: the paschal mystery, the death and resurrection of Jesus and the gift of the Holy Spirit. According to some authors, the Book of Wisdom, the last of the Deuterocanonical books was composed in our era, when Jesus had already been born.
Tobit was written around the beginning of the second century B.C. in Hebrew or Aramaic, but the original text was already completely lost by the end of the second century. We are left with the Septuagint version of Tobit in two forms: one long and one short. The Codex Sinaiticus has a longer version than the Codex Vaticanus and the Alexandrinus. The long text is also contained in the Vetus Latina: important because it predates St. Jerome and preserves an older redaction.