I think the reason that structured, black-and-white morality seems strange to many people is because morality is directly related to the one thing God left up to chance – our will. Everything else in this universe depends on precision and structure in order to work properly: The Earth’s precise distance from the sun, our genetic structure, etc. We think that morality is an exception to this rule since it doesn’t seem scientific, and we’ve never known what it’s like to not have free will. We take our free will for granted sometimes since we cannot comprehend the alternative – being a robot, being a drone. For all we know, this could be worse than Hell itself. We are very lucky to have this freedom, and yet, it is this same freedom that makes it hard to comprehend the existence of universal moral standards.
So I think one way to think about the perfect standard of Heaven is in a scientific, systematic manner, where perfect morality is required because it must precisely fit just like everything else in the universe. But since nothing is impossible for God, and because love is not a formula, He can override this precise fit – required by the perfect universe He created – by sending Jesus.
The other option would be to force perfect morality upon us, giving us no free will. Some might say there is a third option of lowering the requirement for Heaven, but this goes back to my first point that everything in the universe (besides our will) is finely tuned to a precise functionality – some things, like the sun being one millimeter closer to Earth, just don’t work.
In his book, The Problem of Pain, C.S. Lewis explains the nature of such impossibility: “But I know very well that if it is self-contradictory then it is absolutely impossible. The absolutely impossible may also be called the intrinsically impossible because it carries its impossibility within itself, instead of borrowing it from other impossibilities which in their turn depend upon others. It has no unless clause attached to it. It is impossible under all conditions and in all worlds and for all agents.”
Anyway, I’m glad God sent His Son as a way of crossing structural, rigid boundaries, even if it means that not everyone will make it to Heaven because being a robot with no free will is probably quite a bit like Hell anyway.
We live in a universe full of structure – a flawed one, yes, but everything down to the tiniest molecule is in some sort of precise position. Even while we live in such a structured universe, we see structured morality as strange. We will never be perfect, but we must at least accept that perfect morality exists somewhere, somehow, and that trying to get into Heaven by doing good things is a structural impossibility that can only be overridden by Jesus.