Well-researched, but flawed.
This is based on the author's Oxford dissertation. In two introductory chapters, Yang surveys the Sabbath in the Old Testament and in Judaism. He finds an eschatological meaning for the Sabbath in the Genesis creation account. He concludes that there was an increasing emphasis in Judaism on how to keep it at the expense of in interest in why, although he fails to consider that this may simply reflect the documents at our disposal, and not the actual practice of the Sabbath in second temple Judaism. Since the Sabbath controversies in Matthew 12 appear closely related to Matthew's overall understanding of the law in relation to Jesus, he contextualizes the issue in chapter 3 by an examination of that topic. Weakest element of his argument is that he understands Matthew 5:20 as an anti-legalistic statement, then concludes from this that Matthew's warning against legalism was more severe than that against antinomianism. The heart of the book is chapter 4, by far the lengthiest. He sees Matthew portraying Jesus as the fulfillment of the Sabbath (tying in 11:25-30: rest is reinterpreted in an eschatological and Christological sense), thereby rendering a literal observance of the day obsolete, though not wrong. In chapter 5 Yang briefly considers Mt 24:20 and concludes that the mention of the Sabbath is because of the practical difficulties that would be involved in such a flight; it is therefore not right to use this statement as evidence that Mt's community observed the Sabbath. Chapter 6 surveys the non-Matthean synoptic Sabbath material. On the premise of a multiple source (common tradition) theory of Gospel formation, Yang suggests that Mt may have known this material but chosen not to use it because of the danger of "legalistic" (a term he uses carelessly) sabbath-keeping among adherents of his community. Nevertheless, he detects similarities in treatment among the three gospels, which, he suggests, is evidence that they originate in Jesus's teaching itself. A seventh chapter, in which Yang investigates four passages from the apostolic fathers for evidence that they knew and used Matthew's treatment of the sabbath is especially strained, especially since he attempts to turn his negative findings into positive ones. In chapter 8 Yang summarizes his findings and considers their theological and practical significance. Jesus's fulfillment of the Sabbath is the fulfillment of God's original intention and ultimate goal for the Sabbath as revealed in the Old Testament. Although the author claims to be dealing with Matthew's understanding of the topic, and not with the stance of the historical Jesus, his ready acceptance of the historicity of Matthew's account renders this distinction meaningless. It is Jesus himself, not Matthew's understanding of Jesus, that renders it no longer necessary to observe a literal Sabbath, and those of Jesus's early followers who continued in Sabbath observance (such as the women who waited until Sunday morning to visit the tomb) simply didn't understand the implications of Jesus's coming. These criticisms aside, this is a well-researched book, more readable than many dissertations, and will interest all students of this topic.