If genealogy was so central to Jewish people, why did Mark omit it? Also, if Matthew and Luke were following the text of Mark, what made them mention the genealogy of Jesus?
Mark immediately draws attention in his book to two prophecies. He quotes Malachi first, despite that Isaiah is the greater prophet and despite that Isaiah is first in precedence in history Thus, Mark draws attention to Malachi's prophecy.
Mark draws attention to the messenger of preparation and to the messenger of the covenant, who is the Lord himself :
and the Lord, whom ye seek, shall suddenly come to his temple, even the messenger of the covenant, Malachi 3:1 KJV.
Thus, from the very first words of the book, Mark is setting forth the One who, being the Lord himself, is the only proper person to, himself, express the everlasting covenant, the New Testament.
This is also expressed in the epistle to the Hebrews which bears a number of similarities to the book of Mark. One of these similarities is the mention of Melchizedek, who has no genealogy, of whom the writer to the Hebrews states :
Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually. Hebrews 7:3 KJV.
I think that this is the reason Mark begins his book at the place in Jesus' life that he does. Mark immediately (a word used oft in his book) presents John the Baptist, the voice crying in the wilderness, and then immediately presents the messenger of the covenant, the Lord himself.
Mark draws attention, as does the epistle to the Hebrews, to the Deity of the One who is sent to expound the New Covenant.
This is also, I would say, why Mark records the actual words that Jesus spoke on the cross 'Eloi, Eloi' in his own dialect - his own actual speech - rather than, as Matthew, record the Hebrew from which Jesus is quoting. Mark is drawing attention to the very utterance of the Lord, the messenger of the covenant, and drawing attention (as does the writer to the Hebrews) to the importance of the setting forth of the New Covenant.
The aspect of Jesus Christ, the Son of God, which Mark sets forth does not require an account of his genealogy. It would detract from the immediacy of the Person and the message to enter into a detail which others have, already, set forth in different aspects.
The content of each Gospel was determined by the intended audience of each.
Matthew wrote largely for a Jewish readership and so included numerous incidents to show that Jesus was the prophesied Messiah, the fulfilment of OT prophecies. Therefore Matthew includes a genealogy tracing Jesus back to Abraham, the Father of the Jews.
Luke wrote largely for a Greek readership and included numerous incidents about non-Jewish people, centurion and the Perean ministry. Thus, Luke included a genealogy tracing Jesus back to Adam, the father of all mankind.
Mark wrote largely for a Latin readership and selected his incidents accordingly. It is therefore, the briefest of the Gospels and has no need of genealogies on which the Latins we much less interested.
Therefore, while the synoptic Gospels share many similarities and some passages that almost verbatim, they also show some independence from each other in their selection and wording of incidents to suit their readerships.
This is one possible exclamation to your question about why the 4 gospels gave or did not give emphasis to the genealogy of Jesus to establish that he is indeed the promised messiah in Tanakh.
- Mark was probably written in the 70s and the belief at this time among the followers of Jesus was that Jesus was a good man and God adopted him as the son of God at his baptism.
- Matthew & Luke came next around the 80s and by then Jesus was viewed as being the son of God at his birth (hence the genealogies)
- John which was written around the 90s believed that Jesus was the son of God from eternity. So John did not see the need to establish that Jesus was from the lineage of David.
- By around 100-150 Jesus was viewed as God in flesh and firmed in 325 at nicea.
Please refer to this link
In looking at all four Gospels, there are only two genealogies and two accounts of the birth. Matthew presents a genealogy through Joseph and Luke through Mary. In addition, each gives an account of the birth of the birth from the same perspective:
Gospel Genealogy Birth Account Matthew: Through Joseph Joseph's point of view Luke: Through Mary Mary's point of view
Accordingly, once the father and mother's accounts and genealogies are recorded, the inspired texts are complete. That is, in terms of His human birth, there is nothing further to add. Consequently, Mark begins with the adult ministry of Jesus, as he states:
The beginning of the gospel of Jesus Christ, the Son of God. (Mark 1:1 ESV)
The Good News begins when John the Baptist makes his announcement.
Finally, John's account begins by giving Jesus' identity before his birth.
Matthew: Jesus' birth from Joseph's point of view Mark: The beginning of the Gospel of Jesus Christ Luke: Jesus' birth from Mary's point of view John: In the beginning was the Word who was with God
The four accounts are not arranged in the New Testament chronologically. However, based on the birth accounts and genealogies, one could assume a specific audience for each Gospel corresponding to the different types of people as they are first introduced in Scripture:
Mark: Written for Gentiles Matthew: Written for the Jewish people [established after Gentiles] Luke: Written for the Levites [established after the Jewish people] John: Written for the children of God [established after the Levites]
One who was Jewish needed to know the genealogy and birthplace of Jesus in order to affirm He was the Christ. A Gentile's focus is more along the lines of "Am I eligible to enter the Kingdom of the God of the Jewish people." Hence, Mark, written for that audience begins with the Gospel of Jesus Christ...