So... How can we claim the Bible is authoritative when there are two differing lists of supposed Scriptures within Christianity...Two different Bibles? My next question is akin to the first: How do we know with certainty which list is THE list?" Both of these questions center on authority. Who do we trust as our God approved authority able to testify for us on behalf of Scriptures?
It is no wonder that the other religions of the world do not take true Christianity seriously when such fundamental divisions exist within the Body.
The Apocrypha is not included as part of the inspired text because it does not meet the criteria of the inspired canon. Here are just a few examples.
The Apocrypha contains historical errors. In Judith 1:1 Nebuchadnezzar is reigning in Ninevah instead of Babylon.
The Apocrypha contains unbiblical teaching. 2 Maccabees 12 teaches to pray for the dead. Tobit 12:9 teaches faith by works, a clear contradiction to the Bible (Ephesians 2:8-9).
Jesus and the Apostles do not quote the Apocrypha. We do not see it directly quoted in the New Testament.
Finally Jesus tells us where the inspired canon ends in Luke 11:51. He says the prophets extend from Abel (Genesis 4) to Zechariah (2 Chronicles 24:20-21). So the line of prophets ends with the Jewish Old Testament, the Masoretic text that Jesus used as authoritative.
The history of the Apocrypha is interesting. It was not part of the Catholic Church's inspired canon until 1545 AD. No council recognized it in the first four centuries. The historical evidence goes against the Apocrypha. It was incorporated by the Catholic Church in response to the Protestant challenge to several unbiblical teachings such as praying for the dead and penance. Hope this helps.