I grew up on the New International Version (NIV) translation of the Bible. The NIV was originally published when I was in grade school and soon thereafter my Mom got me a NIV Children’s Bible. Later on, in my teen years, I got a Ryrie Study Bible (NIV). The thing I appreciated about the NIV was it was very readable for a young person. One thing I started noticing was that in certain places, for example, John 7:53-8:11, there was a disclaimer of sorts inserted between the text: “The earliest and most reliable manuscripts and other ancient witnesses do not have John 7:53-8:11.”
Most modern versions of the Bible have some kind of disclaimer like this in John’s Gospel as well as the end of Mark’s Gospel (Mark 16.9-20). My English Standard Version (ESV) Reference Bible says “Some of the earliest manuscripts do not include 16:9-20″ right before the end of Mark (I actually prefer the ESV’s language over the NIV’s because the ESV simply refers to earlier manuscripts rather than making a value judgment regarding their reliability). It’s also set apart in the ESV as different by use of double brackets, like this: “[[Now when he rose early on the first day of the week...worked with them and confirmed the messages by accompanying signs.]]”
So the question is, what does this mean?
You may already know that the New Testament was originally written in the Koine Greek language. We do not have the original manuscripts, which is a good thing, because with our proclivity to worship things instead of God, the original manuscripts would be definitely be an irresistible temptation to idolatry. What we do have are thousands of manuscripts in Greek. These manuscripts fall into two “families” of manuscripts: the Byzantine (centered in Eastern Europe) and the Alexandrian (centered in Northern Africa). For the vast majority of church history, the best and most numerous manuscripts were in the Byzantine family. But in 1844 ancient manuscripts were discovered at the Monastery of Saint Catherine on Mt. Sinai by archaeologist Constantin von Tischendorf.
Examined by scholars, these manuscripts were discerned by some to be the oldest and most reliable manuscripts. On the positive side, although they represent an entirely different chain of history and, therefore, line of copyists, their contents were remarkably similar to the manuscripts in the Byzantine family. On the negative side, however, there were some differences. Some scholars estimate the difference to be as much as 5%. In most cases, single verses were missing in the Alexandrian texts (when compared to the Byzantine texts). This explains why in modern versions you might be reading along and notice that your Bible has a verse 4 and a verse 6, but no verse 5 in between (see John 5 in the NIV or ESV). As previously mentioned, a couple of entire passages were absent (from John 8 and Mark 16).
For some Bible readers, these differences can be disconcerting. If the end of Mark is not inspired Scripture, then what happened to the ending? Did it somehow get lost? Or does Mark his Gospel end abruptly, with the disciples in fear (see Mark 16.8)?
But Bible readers need not stress over such matters. No major, or even minor, doctrine is impacted by any differences between the Byzantine family and the Alexandrian family.
Consider the notes on Mark 16:9-20 in the ESV Study Bible:
“Longer Ending of Mark.” Some ancient manuscripts of Mark’s Gospel contain these verses and others do not, which presents a puzzle for scholars who specialize in the history of such manuscripts. This longer ending is missing from various old and reliable Greek manuscripts (esp. Sinaiticus and Vaticanus), as well as numerous early Latin, Syriac, Armenian, and Georgian manuscripts. Early church fathers (e.g., Origen and Clement of Alexandria) did not appear to know of these verses. Eusebius and Jerome state that this section is missing in most manuscripts available at their time. And some manuscripts that contain vv. 9–20 indicate that older manuscripts lack the section. On the other hand, some early and many later manuscripts (such as the manuscripts known as A, C, and D) contain vv. 9–20, and many church fathers (such as Irenaeus) evidently knew of these verses. As for the verses themselves, they contain various Greek words and expressions uncommon to Mark, and there are stylistic differences as well. Many think this shows vv. 9–20 to be a later addition. In summary, vv. 9–20 should be read with caution. As in many translations, the editors of the ESV have placed the section within brackets, showing their doubts as to whether it was originally part of what Mark wrote, but also recognizing its long history of acceptance by many in the church. The content of vv. 9–20 is best explained by reference to other passages in the Gospels and the rest of the NT. (Most of its content is found elsewhere, and no point of doctrine is affected by the absence or presence of vv. 9–20.) With particular reference to v. 18, there is no command to pick up serpents or to drink deadly poison; there is merely a promise of protection as found in other parts of the NT (see Acts 28:3–4; James 5:13–16).
What the reader should also know is that in addition to the King James Version (KJV) of the Bible, the New King James Version (NKJV) of the Bible also uses the Byzantine family of Greek manuscripts for its textual base. This means that verses like John 5:4 are still in the text, and that there is no disclaimer before the texts of John 7:53-8:11 and Mark 16:9-20. All other popular modern translations use the Alexandrian family of manuscripts as the textual base, including the English Standard Version (ESV), Holman Christian Standard Bible (HCSB), New Living Translation (NLT), New American Standard Bible (NASB), and New International Version (NIV).
What the reader can also be confident of is this: whichever modern translation you use (any of the above listed), the basic doctrines of the Christian faith are present and clear.