I believe you need to look at the sacrifice of Christ with the Old Testament in mind. The sacrifice was meant to fulfill a convenant with all of humanity. In the Old Testament God tries to make the first covenant with Adam and Eve, but as we all know they fail. Next is Noah with his family, and Noah's sons fail the covenant. Then comes Abraham as a leader of a tribe (this is where circumcision comes in) This is followed by Moses and the 40,000 slaves. Afterwards is King David and his kingdom. An obvious pattern can be seen, where God makes a covenant with a married couple, family, tribe, forthy thousand slaves, and finally a kingdom...and well...each time we fail God. Clearly God needed someone who was fully human and without sin to complete the covenant with humanity. This was of course fulfilled with Jesus' sacrifice which made a covenant with the whole world (i.e. catholic church [catholic meaning universal...not the denomination]). Why did Jesus have to die the way he did? In the Old Testament it is often stated that to show someone you love them, you are willing to give and sacrifice your all for them, which Jesus clearly did for all of us (As Mel Gibson shows pretty well). The sacrifice of Jesus doesn't necessarily make sense unless you know all the details that lead up to it (and the whole Old Testament leads to Jesus). This is a very very brief explanation, and I wouldn't be surprised if there were a few errors (seeing as I did this off the top of my head.) Hopefully this helps you somewhat...