Superman isn't brave. You can't be brave if you're indestructible. It's everyday people like me and you who are brave, knowing we can easily lose but still continue forward. That's true bravery.I did a little googling and my search traces the quote, or at least the first part of it, to the movie Angus.
But who in fact came up with it isn't what concerns me. What immediately popped into my head when I read it was that it must've escaped this Christian that similarly the supposed sacrifice of God wasn't a sacrifice at all because God didn't die. He (that includes all three of him) is indestructible.
We can't talk of God's bravery or selflessness or about God giving himself. How can the father have given his only son when no such thing ever happened?  God didn't get terminated. He can't. Or are believers saying that the Trinity was, for 3 earth days circa 30CE, whittled down to a Duo? Are there theologians who say that while Jesus lay dead the Second Person of God was nonexistent?
Some may say that Jesus did die. But God isn't a human being, notwithstanding the doctrine of incarnation. And what does it mean to say that he became a terrestrial creature? Surely, theologians and believers aren't saying that while Jesus was alive there was no god out there anymore. Or are they saying that part of God became human? What could that mean? Or are there Christians out there who believe that a supernatural entity literally impregnated a human female, a la Greco-Roman mythology, resulting in the birth of a hybrid--a cross between a deity and Homo sapiens?
Being perfect and all-powerful God can recreate the human Jesus and have him crucified a trillion times, and God would still be God. He wouldn't be any less or more than before this exercise. Being omniscient God knew everything even before he created the universe. Being outside time saying he knew all this before the creation doesn't even do justice to the timeless nature of his knowing. Being omnipotent and having perfect knowledge, it really boggles the mind why God even created this universe--this vale of tears. It can't be by necessity--it can't be that God couldn't have but created this universe--since that would imply he isn't omnipotent.... The problems are legion. The point here simply is that given the presumptions about this particular deity, God couldn't possibly make sacrifices.
We humans are able to make sacrifices because we're mortal, because we can suffer, because we necessarily have to expend energy and resources and exert ourselves in order to attain our objectives, because we're finite in all respects. A being who is perfect, eternal and omnipotent can't be harmed, can't die, can't change, can't suffer, can't make sacrifices. Christians can't have it both ways. Either their deity is just finitely more intelligent, powerful, evolved/developed than we are and thus can still possibly suffer and die and make sacrifices--give something that will diminish it in some way--or it's omni-everything and simply too perfect such that it's impassible and immutable.
Now amongst humans who are those who (in some sense) make a greater sacrifice when they lay down their lives for some cause? If you think about it, it's those who don't have any belief in or deny outright an afterlife. When these people put themselves in harm's way they believe (or know) they're risking the only life they will ever have. On the other hand, those who believe they're going to wake up even after they've breathed their last are of the mindset that even though they put their lives on the line and end up dead they'll still rise up once more like some phoenix (and from then on live forever), with their egos, memory, personality intact.  The fear of annihilation is assuaged by the belief that death is merely the dissolution of the body, that the self, one's "essence" if we may call it that, does not die. So how one understands death makes a difference in how the sacrifice is felt.
1. And what does God being "father" and "son" mean? They're biological concepts and can hardly apply to something immaterial. Even "giving" and "sacrifice" are anthropomorphisms.
2. Here, of course, I'm excluding those who believe that individuality doesn't survive death. Christianity is pretty egoistic in its conception of the hereafter. If I were in the market for an afterlife I'd choose the Hindu version--when we die we will be like raindrops returning to the sea, losing our individual identities, merging with the ocean and becoming just one body of water.