The impulse to do good, the inspiration (yes, the root of that word is "spirit") for all good acts is Divine in origin. However, we may accept or reject God's suggestion to do good. We call that free will.
So those impulses are God given. That impulse to avoid shame is God given. That impulse to be thought of as being courageous is God given. That impulse to give up your seat in the lifeboat is God given. Fair enough, go with that if you like. I have no problem with accepting that. In fact, if I were a Christian I would give you the exact same explanations as I have over multiple posts and told you that the emotions I have given as a reason for self sacrifice are indeed God given.
But your explanation wants to discount all that. It simply wants to say 'Ah, but it's
just an inspiration from God'. Which tells us absolutely nothing. This appeal to divine origin has no explanatory power in the slightest. It tells us nothing except that 'God did it'. And that's not straw manning. Just take it on trust. He's God so He wants us to love our fellow travellers.
And you don't see the problem in that. You'll tell us that love (God inspired!) enables us to do those things. You'll emphasise that one emotion, but discount all the rest, even if you believe, as you must, that they are also divinely inspired. Shame? Oh, well...it counts I guess. A sense of honour? Well, that too. Courage? Mmm. I guess we can include that. Bravery? Heroism? Yeah, they all count.
Your problem is not that you haven't been given an answer. You are just desperate to find ways to disagree.
So we have a spiritual explanation for denying the "selfish genes" enabling the self-sacrificial act. Still waiting on your material explanation -- you know, those atoms and molecules where they are and where they come from.
You want to know about the physical aspects of those God given emotions that enable self sacrifice? Those 'self-conscious emotions, such as shame and guilt, (which) play a fundamental role in regulating moral behaviour and in promoting the welfare of society.'
The Neural Signatures of Shame, Embarrassment, and Guilt: A Voxel-Based Meta-Analysis on Functional Neuroimaging Studies
'Among moral emotions, a sub-group of emotions (e.g., shame, embarrassment, guilt, and pride) defined as self-conscious emotions helps individuals to navigate the complexities of fitting into groups [
1], satisfying the human need of belonging to social groups [
17]. Self-conscious emotions are evoked by self-reflection and self-evaluation [
18], and occur when social norms or agreed-upon social rules are violated [
19], providing an immediate feedback that promotes inhibition or reinforcement of behaviour.'
I'm sure you'll recognise the part about the 'human need of belonging to social groups'...
But you want to know where those molecules actually are. Well, luckily for you, other people have had the same curiosity and have done the hard yards. And you'll surely be pleased to know that we are reasonably sure that the material causes are electrical, physical and chemical processes here:
'At the neural level, shame has been selectively associated with the dorso-lateral prefrontal cortex (dlPFC), the posterior cingulate cortex, and the sensory-motor cortex, whereas embarrassment has been associated with the ventro-lateral prefrontal cortex (vlPFC), the amygdala, and occipital areas, and both emotions with the hippocampus and midbrain.'
Well done, God. Nicely designed I must say.