#1: There are so many versions because there are many different ways to translate from one language into another. The same applies to translations of ancient and modern classics. The original text remains the same, but different translators render it in different ways. You can find many translations, for instance, of Homer's Odyssey (Greek) or Dostoevsky's Crime and Punishment (Russian).
#2: Some Bibles have more books because different traditions in Christianity (Protestant, Roman Catholic, Orthodox) consider more or fewer books to be canonically authoritative. The history of canonization, and the debates about which books are "in" and "out" is too much for me to address here. On the formation of the Old Testament canon, see Andrew Steinmann’s book, The Oracles of God.
#3: Translations of the New Testament are based on ancient Greek manuscripts. These range from long documents down to small fragments (some are tiny pieces of papyrus with only a verse or two). These also differ in age, the oldest fragments dating to the 2nd c. AD. Textual scholars weigh the evidence, based on scientific methods, as to which of these manuscripts most likely contains the original text. Most differences between these manuscripts are very minor (for example, one says "you" and another says "us"). Sometimes a Greek manuscript will contain a verse or half verse or (in highly rare circumstances) a section not found in other manuscripts. Ordinarily, translators will include the "extra part" in brackets or a footnote to indicate that its originality is unknown or questionable. The most well-known of these are the longer and shorter endings of Mark 16 as well as the story of the woman caught in adultery in John 8.
Matthew 17:21 is an example that frequently arises: “But this kind never comes out except by prayer and fasting.” This verse is included in some later Greek manuscripts (known by these symbols: א* B Θ 0281 33 579 892* and a few others) but not in the oldest and best manuscripts. For instance, it is not in Codex Vaticanus (mid-4th c.) nor in Codex Sinaiticus (4th c.). In Codex Sinaiticus, Mark 9:29, “But this kind never comes out except by prayer and fasting” is written as a later marginal note where Matthew 17 is recorded. Later scribes took this marginal note from Mark 9 and *added* it as verse 21 in Matthew’s gospel, thereby harmonizing the two Gospels. The preponderance of textual evidence, however, suggests that the words, “But this kind never comes out except by prayer and fasting” from Mark 9 were never part of the original text that Matthew wrote. For that reason, Matthew 17:21 usually appears in Bibles today only as a footnote. Rather than saying that this verse was *removed* from the Bible–which only leads to confusion–let us rather say that it was never part of the original Matthew 17 text to begin with.
Why is any of this important? None of the original scrolls, the actual scrolls written upon by Paul or Matthew or John, have survived. All we have are copies. Let us be very grateful, therefore, for those scholars who devote their time and energy to studying these ancient documents and applying the principles of sound textual criticism, so that we might be as certain as possible that what we read in the Bible is what the biblical authors actually wrote.
Written by Chad Bird 1517 Scholar-in-Residence