In this chapter, Ehrman addresses the decidedly Jewish character of Matthew's portrayal of Jesus. Now this is in spite of the fact that in Matthew Jesus heaps scorn upon the Pharisees in chapter 23. Even though it is clear that Matthew sees Jesus as the universal savior of the world, he is still the Jewish Messiah in fulfilling that role.
While each of the Gospels recognizes Jesus as the Jewish Messiah, they do so in very different ways. In Matthew, it is clear that one of the main themes is: Jesus is greater than Moses (the Gospel of John makes the same claim but in a much different way). The mention of Jesus' sojourn in Egypt in Matthew 2 makes a parallel to Moses (although the quotation of Hosea 11:1 in Matthew 2:15, "Out of Egypt I have called my son," originally referred to Israel as a people not just Moses or Jesus). The Sermon on the Mount (Matthew 5-7) is clearly the giving of a new law, that seems to implicitly supersede that of Moses (both the "antitheses" in Matthew 5:21-48 and setting of a "mountain" all point to the idea that Jesus is a greater law giver than Moses (the setting is actually a hillside by the sea of Galilee) . Even though Jesus does say that he did Not come to abolish the law (Matthew 5:17), the fact that he has come to "fulfill" the law (Matthew 5:17) means that what he offers supersedes what Moses presented to the people Israel. The story of the transfiguration (present in all three synoptic Gospels) is a blatant statement that someone greater than Moses or Elijah (the law-giver and the great prophet) has arrived (Matthew 17:1-8).
Do not put too much stock in the distinction that Ehrman makes between a "literary-historical" analysis of Mark and a "redaction criticism" analysis of Matthew. The way that Ehrman approaches both Gospels is similar; in discussing both Matthew and Mark Ehrman tends toward the use of a literary analysis that has been adapted for Biblical studies and arose out of the analytical approach to biblical criticism that was originally coined by German scholars as editorial criticism, but since the German word for editor is Redactor, in English it came to be called redaction criticism. But when "redaction criticism" was first developed by historical critical scholars in the 1960's, they were simply taking a Gospel Parallels book and (assuming that Matthew and Luke both used Mark), look to see what changes Matthew and Luke made to the parallel passages in Mark, thereby seeking "theological tendencies" in the author's alterations to the text. But when Ehrman looks at the beginning of Matthew in comparison to Mark, he is not examining parallel texts, but rather what literary devices the author has employed in introducing the topic (Jesus), thus technically it is not redaction criticism the way it was originally conceived. But Ehrman's approach does retain the interest in the author's theological biases.
As Ehrman goes to great pains to point out, the groups of 14s in the genealogy betray a desire to make a connection between Jesus and the greats of the history of the people Israel with the symbolic value of well rounded perfection, both in terms of the lineage and the timing; that is, that it happened in that particular generation (remember that 7 is the number of completeness in the Bible). How historically accurate Matthew's genealogy is - is open for debate; but that is of no interest to Ehrman as he is much more interested in the literary function of this genealogy within Matthew's Gospel.
Concerning the birth of Jesus, Ehrman highlights a feature of Matthew's Gospel that occurs infrequently in the other Gospels, the "fulfillment citation." Matthew's Gospel is full of lines where an event in the life of Jesus is portrayed as fulfilling a specific prophecy in the Jewish scriptures. This is especially true in Matthew's birth narrative. As Ehrman states, there are five such places where a passage of scripture is quoted to indicated that it has been fulfilled in the coming of Jesus. That has the value of emphasizing the fact that Jesus is very much fulfillment of the expectation of the Jewish Messiah.
What Ehrman presents in his discussion on Jesus and the law is mostly the standard interpretation offered by historical critical scholars. Ehrman does not offer any personal theories or unusual interpretations of the material. One thing that Ehrman does not mention that is an often overlooked peculiarity of Matthew is that what a person believes does not seems to have any bearing on that person's salvation or relationship with Jesus as far as Matthew's Gospel is concerned. When Jesus commissions his disciples at the end of the Gospel, nothing is mentioned about what converts are supposed to believe. Rather the command is to go out "teaching them to obey everything I have commanded you" (Matthew 28:20). The teaching of Jesus in this Gospel is all about what he expects his followers to "do." This becomes especially clear at the end of the Sermon on the Mount. In 7:24 only those who hear the words of Jesus and put them into practice can be considered wise. In 7:21 Jesus makes the same point when he states: "Not everyone who says to me 'Lord, Lord,' will enter the kingdom of heaven, but only the one who does the will of my Father in heaven." Nothing about believing here; it is all about doing.
If this would seem to imply a path to heaven similar to the "work righteousness" that the Apostle Paul denounces, Matthew scholar Ulrich Luz (The Theology of the Gospel of Matthew, Cambridge University Press, 1995), says Matthew's approach may look like "works righteousness" but it is not, for two reasons. First the emphasis on "doing" the will of God must be tempered with the acknowledgment that Matthew's Jesus says often that gaining heaven is a "reward" which implies that it cannot be earned (see Matthew 5:12; 5:46; 6:1-16; 20:1-16). Likewise, it the "doing" of the will of God cannot be taken as the sole determiner of gaining heaven because forgiveness plays a major role in the belief structure of Matthew's Gospel (see 6:12; 6:14-15; 18:23-35). These verses make clear that God's forgiveness is necessary for gaining heaven, but that divine forgiveness is still dependent on the human willingness to forgive others. So Matthew's view of what it takes to gain heaven is not a pure "works righteousness" in the sense of earning heaven. But the heavy emphasis on "doing" the will of God (including the Sermon on the Mount as well as the Jewish moral law as presented in the Jewish scriptures), gaining heaven really hinges on whether or not the human can forgive others in the same way that she/he has been forgiven by God.
Luz notes that for the Apostle Paul, Judaism and Christianity are two fundamentally opposing principles. Where as for Matthew, "He sees no rupture between Judaism and Christianity. On the contrary, the Jesus who fulfilled the Law and the prophets represents the true Israel" (Luz, page 148). The only rift is between Jesus and the leaders of Israel (and their followers) who do not do as Jesus teaches. Those who do not follow the teachings of Jesus "exclude themselves from God by virtue of their deeds" (Luz, page 149). For the Apostle Paul, righteousness refers to the action of God in justifying humanity through the death of Jesus. Whereas for Matthew, " 'righteousness' is that which God in his love demands of men and women. 'Righteousness' [in Matthew] means the human path which Jesus' disciples must travel when they allow themselves to be taught, led and accompanied by the Immanuel" (Luz, page 149).
Now back to Luz and Jesus and the Law in Matthew. Luz sums up his interpretation of how the law and the Sermon on the Mount fit in with Christian salvation with: "Living in accordance with the Sermon on the Mount is therefore a path to perfection. One should travel this path as far as possible. On the Day of Judgement the Son of Man will show just where the minimum righteousness lies that is necessary for entrance into the kingdom of heaven" (Luz, page 56).
NOTE: If Luz is correct in his assessment of Matthew's Jesus on role of human deeds and human righteousness for personal salvation, though tempered with the mercy of God on the day of judgment, then the model for human salvation that Matthew puts in Jesus' mouth is very similar to that of the Pharisees of Jesus' time. Of course, Matthew adds the very dramatic qualification that one must accept Jesus as the Jewish Messiah and lord over all humanity, which the Pharisees refused to do.
In another place Luz states: "Our personal relation to the heavenly Lord Jesus . . . none of this will be decisive on the Day of Judgment, only our works" (Luz, page 58). "Matthew rehearses with his readers the absolute sovereignty of the Judge of the world [Jesus], against whom there are no demands that can possibly be raised, but only his assessment of human deeds" (Luz, page 61). Jesus "is now God's Immanuel and the traveling companion of the community [of Christians], the same who is now proclaiming God's commandments to the community , and who is leading them in prayer to their Father in heaven" (Luz, page 61).
All ideas expressed above on the role of the commandments in Matthew and the accompanying quotations are taken from: The Theology of the Gospel of Matthew, by Ulrich Luz, Cambridge University Press, 1995.
One final note about Ehrman and the Gospel of Matthew. For some inexplicable reason, Ehrman did not emphasize the fact that the Day of Judgment when Jesus will return as the divine judge (the Son of Man) is a really big deal in Matthew as should be obvious to even a cursory reading of Matthew's Gospel. Mention of this upcoming event appears over and over as a warning to the reader to shape up and live right. But for some reason, Ehrman completely ignores this.