Use of NT in OT

I just finished writing an article on the Use of the Old Testament in the New Testament, which will be published in the Baker Handbook on the Bible in 2010. For copyright reasons, I can't post the whole article here, but here is an excerpt:

A quotation or allusion to the OT can be pictured as an hourglass. The upper chamber of the hourglass is the context of the OT reference; the neck of the hourglass is the quotation or allusion; and the lower chamber of the hourglass is the context of the NT quote. The NT’s brief reference to the OT is often a way of showing connections between the theology of an entire OT passage and the theology of the entire NT passage. In many cases, references to the OT that at first appear strained make sense when the connections between the theology of the OT and NT passages are observed. For example, the five OT references in Matthew’s birth narratives (Mt 1:23/Isa 7:14; Mt 2:6/Mic 5:1-3; Mt 2:15/Hos 11:1; Mt 2:18/Jer 38:15; Mt 2:23/Isa 11:1) are troublesome because some appear to ignore the meaning of the OT passages. However, a careful reading of the context of the OT passages reveals a common theme: the desperate plight of God’s people and their promised rescue. Matthew is showing a connection between God’s OT promises of rescue and the NT birth of the rescuer...

There are a variety of reasons for a NT author to make use of OT material. It is important to understand first what the NT author is not doing. The NT author is rarely engaging in exposition of the OT text; that is, he is not trying to merely explain what the OT author meant in the fashion of a commentary or expository sermon. The NT author has his own message, and he refers to the OT to advance that message. This is not to say that the NT author is disinterested in what the OT author meant; rather, he is interested in the theology of the OT passage and how it can be used to advance the NT author’s message.