For those of us who have a sense of the importance of history in the practice of our faith, we are aware that there was a major socio-political religious movement called the Protestant Reformation. During the Reformation, many major tenants of the evangelical faith were rediscovered leading to the movement of several newly formed Protestant denominations out of the corrupted Roman Catholic church.
One of the major factors motivating this exodus was the desire for purity of Biblical doctrine - salvation by grace alone, through faith alone was among the most well known of these doctrines. Ironically, however, with all of the focus on the recovery of sound doctrine, one of the major casualties of the Reformation was the loss of distinction between (or even mention of) the Old and New Covenant.
It could be argued - and in another place perhaps I will - that the entire Bible can be held together by a proper understanding of the movement from the Old Covenant to the New. This was not the case with the Reformation. The reformers argued that the movement in the bible is actually from the so-called "Covenant of Works" to the "Covenant of Grace."
If you have a difficult time finding this language in the bible, it is because it is not there. This meta-structure that the reformers erected around the myriad teachings of the Bible had the best of intentions, but in the end has become just another man-made system developed to keep God in a box where He can be controlled. But, if you look for instances of the language of Old and New Covenant you will find it everywhere.
So what? With all the 'real problems' in the world, who cares about some fine line of division between two Theological opinions? Questions like this ignore one of the most basic understandings of the Christian faith: that our actions proceed out of what we believe.
The point is that while the Reformation was a God-given blessing to the church, it was still just a human movement of rediscovery not unlike the Renaissance or the Enlightenment - wrought with error intertwined with divine truth. One of those major errors was the construction of the monstrosity of the Covenant of grace/covenant of works paradigm. The casualty was the loss a proper understanding of the Old Covenant/New Covenant distinction, or in some churches the loss of the mentioning of this distinction at all.