Simply put, it emphasizes the manner in which God saves redemptively through the historical reality of the Savior (that is was a true event in time and applicable to everything in the bible).
The focus is grounding everythinig in the reality of the historical context of a real Jesus, real virgin birth, real life, death and resurrection. That Christ, then, speaks to everything that is exegetically tenable about what is happening through every page of Scripture. Everything is grounded and seen in the need for redemtoion because of sin, and by the cross.
You could probably check out any work on what is known as "Christ-centered preaching". Christ and his work is the goal of redemptive history, and this type of preaching is always concerned with that goal, regardless of which text is being preached from. I didn't get a chance to study it very much at RTS because I dropped out too quick, so sorry if that sounds overly simplistic.