Uthenga Wabwino Ndi Chilamulo

What is the relationship between the law and the Gospel? Did God set aside His law to save sinners? When Christ came into the world, was it to instruct sinners on how they are to keep the law as a rule of life, or did He come to fulfill the law on their behalf? Since Christ did fulfill the law, what is the obligation of the believer to the law today?