(Pro 30:6 KJV) Add thou not unto his words, lest he reprove thee, and thou be found a liar.
One of the big questions that the early church struggled with was, “What is to be included in scripture?” It was an honest question and different people had different understandings. The results were hammered out over a couple of hundred years and we come up with the 66 books that are accepted by all Christians and the Apocrypha which is added by some. Personally I don’t feel like anything beyond the 66 is to be included.
Then comes the question of translation and manuscripts. That will probably never be agreed on by the entire church. In the disagreement you have two large groups of scholars. You have one group that is honestly trying to get to the best understanding of the original sources. They are on the side of the angels and have the support and guidance of the Holy Spirit. The second group are the ones who are simply trying to be the most clever kid on the block. To them it is an intellectual exercise at best and an ego trip a little further down the road.
So? For those of us in everyday life we need to accept what this verse is telling us. There is a body of writing that is the Word of God. Other things may have a use but they are not on the same level. Try to understand and ask all the questions you want but do not add or subtract from what was given to us.