Scripture has not been preserved and to suggest it has is a lie.
Mark’s gospel has a short and a long ending, likely because the original ending was lost.
Revelation was reconstructed in the Textus Receptus by Erasmus based on the Latin Vulgate because entire swaths of it were missing from the Greek manuscript he had.
Notice that this author too, shares the same concerns as other theologians and scholars have, which I have also voiced. Matthew was considered earlier than Mark for a couple of reasons, chief among them being that Mark’s gospel tells us nothing about resurrection. This keeps us from certain theological problems. However, it’s incredibly difficult to maintain that view any longer and in fact, only a handful still do. So, either the resurrection isn’t part of the Gospel, or scripture hasn’t been preserved!
If you have an NIV or ESV, search for the following verses: Matthew 17:21, 18:11, 23:14, Mark 7:16, 9:44, 9:46, 11:26, 15:28, 16:19-20, Luke 17:36, 23:17, John 5:3-4, 7:53-8:11, Acts 8:37, 15:34, 24:6-7, 28:29, Romans 16:24. These are samples from just the NIV. Look here for how other translations similarly keep and discard scriptures: https://en.m.wikipedia.org/wiki/List_of_Bible_verses_not_included_in_modern_translations
They were not carried over into these translations because the earliest manuscripts do not have them.
There are many “codecs” from which we get our translations. Notice the difference here between the KJV and the Codex Sinaiticus (The earliest and oldest complete New Testament manuscript): http://www.biblicalarchaeology.org/daily/biblical-topics/bible-versions-and-translations/absent-from-codex-sinaiticus-oldest-new-testament/
The various codecs themselves have wildly variant texts.
For the purist who has made an idol of the KJV, there are no differences in opinion on its status in regard to it’s faithfulness in communicating what the Greek and Hebrew authors had written. Universally, scholars agree that it is the utterly worst translation one can read, if understanding the content of the works they translate is the goal.
I can go on and on but these are all matters of fact. There are no arguments. There are fundamentalist pastors lying in order to tell you the Bible is God’s word. It’s not. Jesus is. The commandments of the Torah and the Memra/Logos are the only things scripture ever called God’s word, not a book. Whatever expresses God’s will on Earth is God’s word. Christ and Law, that’s it! The pastor is making a move to say scripture is absolute so that he can say his interpretation is absolute by saying there’s only one interpretation and many applications. This is so far from the truth that it’s repulsive.
The credibility of these pastors is, has, and continues to be why Christianity continues to be in sharp decline.