One thing I have come across is that in John chapter 5, where it talks about the healing at the pool on the Sabbath, older translations say in verse 4 “for an angel of the Lord went down at certain seasons into the pool and stirred up the water”. I am very convinced that it was written by a scribe and he put it into the margins because the older manuscripts do not include that and it must not be in the originals. Now the newer 2011 ESV translation does not include that , so my question is would stuff like this be all over the Bible ? Should I check more interlinear Bibles when I study for teaching because I would like to teach as accurateloy as I can. Also where can I find out more things like these so I can be careful about things like this, and what do I do about isues like these when people approach me?
I appreciate your concern to be careful and accurate when you teach others. I answer this and most of your other questions in my book “Reasons for Belief.” You really need to get a copy of this book! It is available at www.ipibooks.com. In this book I list nearly all the major manuscript questions in the New Testament. There are five or six significant manuscript questions, plus a lot of very minor ones. So if you are asking if significant manuscript issues are “all over the Bible,” the answer is no. In the final analysis, we can be quite confident of our received Greek New Testament.
Scholars are unanimous that John 5:3b was not in the original John. Probably, a later copyist, in an attempt to help the reader and to explain to us why people waited at the well, added the section about the stirring of the water. Like you say, it was probably inserted into the margin, and the original one to add this did not intend to insert it into the text, but later, someone else included it in the body of John. The only reason this ever ended up in any English translation is that, when the King James Version and the other very early English translations were made, scholars only had access to fairly late manuscripts–ones which included the extra words. Four hundred years later, instead of a couple dozen Greek manuscripts, we now have about 8000 Greek manuscripts, including dozens which are from the first four centuries. This information has allowed us to be much more confident about the accuracy of our best Greek text of the New Testament. When they looked at the evidence, scholars discovered that none of the earliest manuscripts included John 5:3b. I believe the oldest manuscript with this addition is from the sixth century. The conclusion, then, is clear. I discuss this and other manuscript issues in Reasons for Belief.
As for what you should do: that is simple. When people ask you, simply tell them the facts. There is no question about the reliability of the New Testament text, at least as far as this particular manuscript issue is concerned. You can point those who ask about this “problem” to books which explain copying errors and translation issues. Because the scriptures were copied by hand, of course minor changes crept into the text, but because we have many thousands of manuscripts, we are able to reconstruct the original with a very high precisoin. I believe that those who are willing to check out the question of biblical reliability will have their faith in the reliability of the scriptures increased by the process of studying it out.