If you are committed enough to another person that you actually ask them to spend the rest of your lives together, to live with each other, maybe raise kids, in sickness and in health, forsaking all others etc then I personally don't see that you need to register this commitment with anyone other than the person to whom you're making it. As far as I am concerned, the moment my wife said yes to the question 'Will you marry me', that was it. We were committed.
Yes, we did go through a legal ceremony. No friends, no family, just myself and my wife and two witnesses, one who was all but dragged in off the street for a few minutes to help out. And yes, we ended up with a legal document. And I'm not even sure where that document is right now - although I'm sure my wife has it squirrelled away somewhere, just in case there are some legal ramifications at some point re wills or something equally mundane.
But it has nothing to do with our commitment to each other. I can't see how it could.
This is a common argument. If you'll note from my previous posts, I was willing to concede your relationship as perfect. The reason for the questions that followed was to ask, "OK, for the purposes of this conversation your relationship is fine. But do all relationships last?" I believe you've conceded that not all relationships last, and further that when they end, it causes harm. So, we're starting from that point.
Actually, all the things that come to mind are shared in some fashion by some other religions. There are differences. But they're not unique. A father and son. A trinity. A virgin birth. A resurrection. Heaven and hell. Creation, floods and an evil devil figure. What might be interesting is if I asked you what sets Christianity apart from all other religions and we can investigate if any other at some time has had a common concept.
OK. It's a fair question, so I'm willing to entertain it. But I've never really thought about it before. It doesn't matter to me if Christianity has a unique morality. Maybe that's the conclusion it's coming to - that it doesn't matter to either of us.
As we discuss this, and my thoughts become clearer, maybe the only 2 points I could make have already been made: 1) That the English Common Law was influenced by people who were Christians, 2) that the English Common Law is different than pre-colonial law in other cultures (e.g. India and Arabia).
Maybe how they are different doesn't matter to you, as you'll argue that they simply had different arbitrary starting points and (for all "reasonable" cultures) they are converging on a utilitarian ideal. If so, I would disagree. I would say they are simply changing with the whims of the times, always have, and always will. People want to be free to do whatever they want to do, so they push for that. Eventually, when they realize that being totally free means other people feel no obligation to help them, and everything collapses about them, they sheepishly agree to some constraints. And then set about pushing to be totally free again.
But, to answer your question, I would begin with this. What makes Christianity unique is Christ. If you want to take it further than that, I'll have to think about it. My first thought would be: If Christian morality is unique, it would be unique in what it chooses to distinguish as moral and immoral as a total set. Think Venn diagrams again. Christians may share with Hindus in calling thing A immoral. And they may share with Muslims in calling thing B immoral. But as a total set, only Christians call things A, B, C, etc. immoral. Further, they are unique in that only they punish thing A with aa, thing B with bb, etc.
Most (if not all) cultures mark certain killings as murder (i.e. as immoral). If Christianity is unique, it would be in what killings are marked as immoral and how they're punished. I've not studied that enough to be able to say if that's the case, but my expectation is that there are nuances regarding murder that are unique to law systems established by Christians. On a different issue, it's easy to note that Christians lobby for marriage between any man and woman who desire a sexual relationship, and your morality does not lobby for that.