I would say it's both, actually. But I do agree that the OT brings a whole lot of revelation to the NT. Understanding the OT is essential to understanding the NT. As well as vice versa.
I remembered wondering, where does the importance of the blood come in?
Without the OT we wouldn't know the Power that is in the Blood. And all the importances of the sacrifice and the blood.
Plus, theres just a whole lot of information in the OT that the NT writers kind of take for granted that everyone knows...