Markan Priority vs Matthean Priority

[I apologize if you find spelling/grammar errors, english is not my first language][Although my opponent make a positive case for Matthean priority in his first argument, i will not adress him until round 3, instead,i will make a positive case for Markan priority]I will unfold my first argument in three sub-arguments:1.Mark's Gospel is the shortest gospel, and writers tend to expand writings more than contracting them, therefore, Mark's Gospel was first and Matthew and Luke used it as a source.2.In places where Mark's Gospel makes mistakes or says embarrassing and/or meaningless stuff, Matthew and Luke embellish or omit the embarrassing and/or meaningless stuff of Mark.3.Mark's Gospel presupposes some knowledge that a later audience could not have access to, therefore, Mark's Gospel was written first and the other two evangelists use Mark's Gospel as a source, clarifying the data omitted by Mark in their own gospels.[This does not pretend to be an exhaustive defence of Markan priority, there are works by professional scholars (not an amateur scholar one like me) who defend this position very well [See “The Case against Q” by Mark Goodacre) ]Sub-argument #1: Mark's Gospel as the shortest oneIt should be noted that when we compare the synoptic gospels there is a striking “coincidence”, that is, that virtually all of Mark's Gospel is contained in Matthew and Luke, with little if no content that is unique to Mark, that is to say, virtually all the text of Mark is contained in the other two synoptic gospels.For example, in Mark's Gospel, the infancy narrative and the Lord's prayer are absent, and it is hard to think that if Mark is writing after the other two he is going to omit that two important episodes and a lot of other material that it is present in the other two gospels.We can measure Mark in terms of verses: MatthewMark LukeVerses1068 661 114997% of Mark's Gospel is contained in Matthew and Luke (Matthew containing 94% of Mark and Luke containing 79% of Mark), while in the other two more than the half of their content is information that cannot be found in Mark's Gospel (Being this information called the hypothetical Q source). We should note that Luke's Gospel begin with a preface that characterizes most antiquity historians:“Inasmuch as many have undertaken to compile a narrative of the things that have been accomplished among us, just as those who from the beginning were eyewitnesses and ministers of the word have delivered them to us, it seemed good to me also, having followed all things closely for some time past, to write an orderly account for you, most excellent Theophilus, that you may have certainty concerning the things you have been taught.” (Luke 1:1-4, ESV)Here Luke is making the claim that he investigated the eyewitnesses and sources that talked about the events that have taken place, being explicit about a fact, that he was not and eyewitness and that he needed to use earlier sources to build his work, making very plausible the usage of Mark's Gospel by his part.Sub-argument #2: Mark's Gospel as historically poorer/meaninglessVarious passages in Mark's Gospel can be pointed to illustrate the point:•As it is written in Isaiah the prophet: “Behold, I send my messenger before your face, who will prepare your way, the voice of one crying in the wilderness: ‘Prepare the way of the Lord, make his paths straight’.” (Mark 1:2-3, ESV) In this passage we see that the evangelist is quoting two texts from the Hebrew Bible, in verse 2 Malachi 3:1, and in verse 3 Isaiah 40:3, but in these quotations we note a remarkable mistake, that the quotation from verse 2 is not from Isaiah, but from Malachi, a embarrassing detail that the other two evangelists omit in order to avoid errors. •And he said to them, “Have you never read what David did, when he was in need and was hungry, he and those who were with him: “how he entered the house of God, in the time of Abiathar the high priest, and ate the bread of the Presence, which it is not lawful for any but the priests to eat, and also gave it to those who were with him?” (Mark 2:25-26, ESV). Plain simple, here the author is mistaken in putting the phrase “the time of Abiathar the high priest” in Jesus's mouth, because in accordance to 1 Samuel 21:1-6 (the passage where this incident is recorded) the high priest was Ahimelech, Abiathar's father, not Ahimelech himself. And here is when we note the embellishment from part of the other two synoptists, because if we look for the parallel verses in the other gospels here is what we see:oHe said to them, “Have you not read what David did when he was hungry, and those who were with him: how he entered the house of God and ate the bread of the Presence, which it was not lawful for him to eat nor for those who were with him, but only for the priests? (Matthew 12:3-4, ESV)oAnd Jesus answered them, “Have you not read what David did when he was hungry, he and those who were with him: how he entered the house of God and took and ate the bread of the Presence, which is not lawful for any but the priests to eat, and also gave it to those with him?” (Luke 6:3-4, ESV)What a remarkable coincidence! The phrase “the time of Abiathar the high priest” that is present in Mark's Gospel is omitted in the other two, and here the explanation is simple: the other two gospel authors (Luke and the author of Matthew's Gospel) were better informed than Mark and knew that he made a mistake attributing that phrase to Jesus, because that information in Mark is incorrect, and because they were using Mark's Gospel as a source they omitted this passage knowing that it would exalt the literary quality of their respective works.•“And a young man followed him, with nothing but a linen cloth about his body. And they seized him, but he left the linen cloth and ran away naked.” (Mark 14:51-52, ESV)What a weird statement! Totally bizarre and introduced in an abrupt way. It is really hard to see why the author added this to the text (perhaps it was of interest for his audience, or maybe the young man of the incident was the evangelist himself [some scholars would argue for this hypothesis, but because this contradicts tradition, I tend to dismiss it as wrong ]) and for very good reason, it does no get the privilege to appear in the other gospels, making my point, Luke and Matthew keep this incident out because this was of no interest for their audiences and/or because they saw this as meaningless and wasting space in their writings, because they were basing their passion narratives out of Mark's Gospel.Sub-argument #3: Mark's Gospel as historically earlierI can make the case that Mark's Gospel was written around 36-43AD, when there was still public knowledge that Caiphas was the high priest in turn.In the passion narrative, there is an episode that has an omission that is of special interest for us, in Mark 14:53-63, the author is giving us a vivid image of Jesus's trial before the Sanhedrin, but what an interesting detail, the name of the high priest is not told, but in the passion narratives in the other gospels (Matthew 26:57-67, Luke 22:63-71 [Although Luke does not mention in the passion narrative the name of the high priest, he does mention it in some other place, Luke 3:2]), you have the name of the high priest mentioned in a handful of occasions, meaning one thing: that Mark was writing his gospel in a time when Caiphas was still the high priest, not naming him because his position still was of public knowledge; and that Matthew and Luke were writing time later, because they mention his name to clarify to their audiences in what moment and who was the person who condemned Jesus. Or more specifically, that Matthew and Luke used the Gospel of Mark as a source of their gospels (this time for the passion narratives) and added details that Mark's audience knew, but that the Matthew and Luke audiences did not.