@Maniac: In some respect, yes. We do understand a vast majority of the OT because we have the NT, and it explains much of the OT. I do believe that there will be some parts of the NT that we will not fully understand until the second coming. Such things are:
--How is a person saved? Is it by man's free will to accept Christ as Savior or is it by God's divine election and man has no choice?
--How will the events of the end times unfold? In what order? What will the signs be?
--Will there be a rapture of the church, and if so, how will it unfold?
These are a few, but we can say for certain that we know how the church is to conduct itself. That is spelled out very clearly in Paul's letters to the various churches. There will also not be any discrepancy on issues of morality--those have stood since the beginning of time. We know what is right and wrong, good vs evil. The parts that are unclear are those parts that deal with the age to come. Just as the OT didn't understand the age to come (the NT) but did understand how they were to conduct themselves prior to the coming of the Messiah, the NT will not fully understand the second coming but will know how to conduct themselves prior to His second coming. Paul said "For we know in part and we prophesy in part, but when completeness comes, what is in part disappears...For now we see only a reflection as in a mirror; then we shall see face to face. Now I know in part; then I shall know fully, even as I am fully known." (1 Cor 13:9-12). To this, Paul was answering his own questions that he posed to the Corinthian church as to the dispensing of gifts and the removal of quarrels among the brethren. He was not pointing to issues about morality, or suggesting that those declared as apostate (in other words "those who have departed from the truth") are actually part of the church and that the church simply didn't understand it. Paul said to cast these people out. We have the ability to recognize false teaching on a vast majority of things, but on the things to come, Paul says, it is as looking into a mirror (they used bronze instead of glass, so images were not crisp as we have them).
So, its issues about how Christ's second coming will occur that is in dispute.
@ora: yes, morality does need a context. Laws were established to define morality, not the other way around. Before the Law of the OT, good and evil existed, as did right and wrong. The Law was created so that men could identify it and see their sin. The Law in no way makes people righteous, but it instead exposes our inadequacies and the need for a Savior.
I've discussed the the issues you're raising now in the past, so by all means refer to what I have said before. We have one Author. He alone declares what is good because goodness and holiness and righteousness are inherent qualities of God, and goodness and holiness and righteousness stem from God. Furthermore, we are only defined as good, holy and righteous THROUGH Him, and apart from Him, there is nothing good in us. We can do good things, but we ourselves are evil because we do not have God.
God defined marriage, only He can abolish it. God defined gender, and only He can alter it. I'm not here to quibble science or man's law, because I know what science and man's law say, and these are no less divided than anything else.
Think of it this way: at our school, administration has declared that no student is permitted to wear ear buds during school hours. Any visible buds are to be confiscated because, according to them, it is an issue of safety since students cannot adequately hear what is going on around them. There are many who have issue with this rule, and many teachers take it upon themselves to allow students to use ear buds during class. In the end, it is not up to the teachers, because they are under the authority of the administration of the school. It doesn't matter that they believe that students that are permitted to use ear buds work more quietly, and they can use ear buds as a reward for good behavior. It doesn't matter that the faculty can argue that if a student turns his music down that it is not a safety concern. What matters is that there is only one governing body that has the right to declare that the use of ear buds is wrong and anyone violating that rule is equally in the wrong.
Now, please don't get offended that I'm comparing ear buds to a more sensitive issue. I'm merely using something simple to explain something complex.