Originally posted by bbarr
So, if my brother dies before impregnating his wife, I am obligated to impregnate her and raise the child as my brother's? If I do not do this, have I sinned or not?
No, but if you were Christian, and your brother dies, you (and/or your family) would be under obligation to care for your brother's widow.
I think the "law" in Due 25:5-6 are is the logical implication of the Ten Commandment. In that culture and time, the way to assure that your brother's family line did not end, and to assure your brother's widow was cared for - one kept the widow "in the family" by having her become the wife of the closest kin (technically it did not have to be the brother if he was already married).
Now today, the Gentiles are included in the Covenant with God through Christ - and the importance of maintaining family lines (genealogies) and inheritance customs have changed. But the Law is the same - and the obligation it puts the Christian under has not changed.
So marrying your dead brothers wife so that she could continue his family line, is not so much a law as it is the practical application of the Law.
My view at this time, which is still being worked out, is a Christan must not ignore any OT laws, but must understand them with respect to the New Covenant that was established by Christ's blood. Christ being the ultimate sacrifice for sins, and the final High Priest and Mediator between God and mankind.
Things like culture and custom are also important (but not primary) to understand the correct application of these laws.