Hebrews 9:15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance.
In attempting to answer the above question, I have often heard the verse in Hebrews 9:15 used. Supposedly the blood of Jesus works in the past as well as the future, even the past before His earthly ministry. This response, of course, raises other questions: Who are the ones under the first testament who receive redemption under the new. Does the first testament address
Any assumption, that some before Christ will enjoy the benefits of Christ's new testament, means there has to be a way for people to be accepted without following the church's salvation prescription, since there was no way that method could have been followed by those who died before the church even existed. If those before Christ could gain acceptance by another way, then one rightfully asks why that couldn't happen now.
The church can simply say that God can change the rules as He sees fit, granting special privilege to some and not others, but that contention explains nothing and demeans God in the process. There is little wonder that the church never deals with questions like that above except in the most simplistic and superficial way. Luckily for them, the reliance on fear and unquestioning faith as the mainstays of Orthodoxy allow superficiality to prevail in almost all cases.