Questions (there are several here):

Let us take the final 11 verses of Mark for which the earliest evidence is
non-existent. Why and by whom were they later added? Why was Jesus
described as riding on a donkey? Because the writer knew it would be seen
as the fulfilment of OT prophecy and would therefore bolster his Messianic
status. Much as you obviously yearn to believe that every word in the
Bible is divinely inspired I am sure that you have read too much not to
have the slightest misgivings. I have no quarrel with anyone who takes up
the self-denying path of the charismatic teacher Yeshua. He calls us still
to be the highest and the best that we can be and presents us with a
standard of conduct that we can only struggle to achieve.
We have however one small torch to guide us through the surrounding gloom
and that is REASON and we cannot afford to lose it. Religion wanted
Galileo to assent to a theocentric earth and deny that the earth rotated
round the sun. I stand with Galileo “Eppure, si muove!”

Answer:

About Mark 16:9-20, yes I agree with you that the manuscript evidence
leans toward excluding that section from Mark. This is one of only about
three or four significant manuscript issues in the New Testament. The
other fairly significant questionable passage is John 8:1-11. In the case
of the Mark 16 passage, the three most important early manuscripts, Codex
Vaticanus, Alexandrinus and Sinaiticus all do not include this passage.
Codex Bezae, from about the same time, does include this passage. None of
the very early church fathers quoted from this section. It may be a
genuine piece of apostolic writing, perhaps even from Mark, which was
“pasted” onto the end of Mark. It is also possible that a copyist simply
added an ending to Mark. I am not sure. The germane point on this is
that only a miniscule proportion of the New Testament text is in doubt,
including John 8 and Mark 16, as well as a couple of even smaller pieces (
for example Acts 8:37, which is not really controversial,actually).
Virtually the entire New Testament text is considered to be a reliable
part of the original writings. I have written a chapter on this in my
book Reasons for Belief. I believe that whether one includes Mark 16:9-20
does not have a significant impact on one’s understanding of the gospel
message.

In my opinion, the reason Jesus was described as riding into Jerusalem on
a donkey is that he rode into Jerusalem on a donkey! What possible reason
would the gospel writers have in making up this story if it were not
true? The fact is that in the 60’s AD there were still thousands of
eye-witnesses to the events recorded in the gospels still alive who could
easily have refuted the gospel accounts if they included falsehoods. If
the gospel writers were trying to bamboozle people, they would have been
better advised to not include such easily-refuted details, unless they
were actually true. Luke quoted Jesus as saying, “Everything must be
fulfilled that is written about me in the Law of Moses, the Prophets and
the Psalms.” (Luke 24:44) Jesus was well aware that he was fulfilling all
the messianic prophecies. One could argue that he cynically went about
fulfilling the prophecies so that he could claim to be the Messiah. One
problem with this is that the Messiah had to be born in Bethlehem (Micah
5:2) which was hard for Jesus to arrange. The Messiah had to be “sold”
for thirty pieces of silver (Zechariah 11:12). He also had to be
crucified (Psalms 22:16). It would have been hard for Jesus to have
arranged these events (unless he is the Son of God)! The skeptic can
argue that these facts were made up, but there is no evidence to support
this contention. Besides, the fact that Jesus was born in Bethlehem and
that he was crucified are attested to by non-believers in the first and
second century. No, I do not believe it is reasonable to assume that the
gospel writers were liars. I cannot absolutely prove it, but I believe
the most reasonable explanation of the gospel account is that this is what
actually happened.

Do I have misgivings? Yes I do. I am a careful thinker. I am a
scientist. I keep a mental list of difficulties. What I have found is
that over time, as I do research into historical background, as I study
the original texts more carefully, as I consider scientific implications
of Bible statements, I find that most of my questions are solved in that
the Bible is shown to be accurate–to be inspired by God. Are all my
quesitons answered? No. However, with time and study, the overwhelming
evidence for inspiration has given me more and more reason to give the
Bible the benefit of the doubt concerning things which I cannot prove.
Can I prove that Esther chapter three is inspired (to choose at random)?
No. Is the case for inspiration overwhelming? Absolutely yes! Should I
remain skeptical? Certainly.

As Jonathan Swift said, “It is impossible to reason a man out of a belief
he was not reasoned into in the first place.” I teach a class on
deductive and inductive methods of reason. I regularly honor philosophers
such as Kant, Hume, DesCartes and others who used reason to analyze human
knowledge–to study epistemology. I agree with Thomas Aquinas that if
something is true, it must be reasonable. I believe that the only
reasonable conclusion of the matter, based on the evidence is that the
Bible is the inspired word of God. Having said that, I am glad that
reason is not the only torch we have to live by. Reason is a very
powerful tool given to us by our Creator, but he has given us an even more
powerful light: the gospel of Jesus Christ.

I am a huge fan of Galileo. I just taught about him in my philosophy of
science class today. Galileo said, “The Bible was written to tell us how
to go to heaven, not how the heavens go.” I agree with him. I agree with
Galileo that we should not read the Bible as a science book, but that we
should allow nature, the creation of God, to speak for herself. Like
Galileo said, (to paraphrase) God is revealed alike in the inspired Word
of God and in his creation. Galileo acknowledged that God revealed
himself in scripture and in the beauty of his creation. I agree with
Galileo on this. By the way, the Bible never said that the earth does not
move. Unfortunately, Catholic theologians, beginning with Thomas Aquinas,
took the word of Aristotle on this. We should not make that mistake.
FYI, many believe that the story of Galileo saying, “but it moves” is
apocryphal. I am not sure on that one. Galileo was a stubborn man (for
good reason), and this is the kind of thing he may well have done.

Respectfully,
John Oakes