After considering the idea of justice, Tim Keller moves to the topic of Justice and the Old Testament in his 2nd chapter of Generous Justice. This chapter is about how to interpret the Old Testament law with justice as the example. I think that best summarizes it. Keller does this to answer the question of whether or not the laws of the Old Testament are binding on Christians today.
This is a thorny issue, and your answer reflects your method of interpretation. Dispensationalists, Covenant, and New Covenant theology answer this question differently. Keller comes from a Covenant Theology perspective. He recognizes the differences between moral, ceremonial and case/civil law in the Old Testament. The New Testament is pretty clear that Jesus fulfilled the ceremonial law in a way that means it is not binding on us any more. We are ceremonially clean in Christ, and He is our Sacrifice which brings pardon and fellowship.
“So the coming of Christ changes the way in which Christians exhibit their holiness and offer their sacrifices, yet the basic principles remain valid.”
Keller brings a concept from Craig Bloomberg into the mix. “Every command reflects principles at some level that are binding on Christians.” So, Christians need to be ceremonially clean, have a sacrifice for sin etc. The Christian looks to Christ for all this and more, however. The need still exists, but the reality is in Christ. Romans 12 teaches us that additionally we offer our whole lives in view of this great mercy. We offer the sacrifice of praise (Hebrews), not the blood of animals or food offerings.
Cavman Considers 