Why did Martin Luther separate good works from faith?

All Christians everywhere believe faith is required in order to be saved. No one can be Christian if they don't even have faith, right? And in order to be Christian and even have the hope of heaven, one must accept Jesus as Lord and Savior. However, the Bible is very clear in stating faith without works is dead (James 2:20,24). And likewise, good works without faith is dead. If both faith and good works are equally dead on their own, but faith is needed to get to heaven and good works are the sign of true faith, then doesn't that necessarily mean that in the context of salvation the two go hand-in-hand? So why in the world did Luther separate them, or at the very least, why the emphasis of one far above the other?