Context: having noticed the difficult dialogue between Jordan Peterson and Sam Harris, I thought my input may ameliorate the situation.
Basic causal chain:
Fundamental existence i.e. “God” i.e. YHWH (“I am who I am” / “I will be who I will be”) => (Physical) Universe => Evolution => Human biology / physiology / psychology / reward system (“utility function” / “preferences” in Economics)
[A person’s identity can be said to be fundamentally dependent on his preferences. E.g. I am biologically wired to like chocolate; it is an unchangeable / definitive part of me.]
“Objective” morality can be derived rationally (without immediately resorting to “God”), to the extent that human beings’ (subjective) preferences overlap, so that everyone’s rationally derived optimal behaviour (“strategy” in Economics) i.e. what they should do to maximally please their reward system (maximise their utility function), can be described by a common set of rules / goals.
[Due to the great degree of similarity between human beings, this is fairly self-evident. I.e. “pain is real”, as Jordan Peterson cleverly expresses in layman’s terms, and pain is real to everyone in approximately the same way. (Everyone subjectively likes chocolate, so that we can agree on the “objective” moral principle that it is good for man to eat chocolate.)]
When a common (objective) set of goals is agreed upon on the basis of everyone’s overlapping (subjective) preferences, we then have a sort of universally true utility function, from which optimal strategies (“laws”) can be derived (e.g. via decision theory) to govern human behaviour. Everyone will want to “obey” these “laws” simply because it is in their own self-interest (“self-interest” can include the interests of those around you, thanks to this human feature called “empathy”).
Christianity, through its long continuous tradition, has managed to embody precisely the sort of “objective” morality that has resulted in the success of Western civilisation.
[Many people manage to see the beauty of the morality embedded within the bible, in spite of the irrational interpretations imposed upon it by the hordes of “Christian” teachers peddling their ignorant / wilful theological absurdities.]
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With sufficient scientific advancement (especially in Economics / Psychology), people like Sam Harris might find themselves deriving via purely rational inquiry the same sort of morality already achieved through Christianity’s long history.
[Of course, this does not exclude the possibility that the pinnacle of moral enlightenment lies somewhere beyond what has been achieved via Christian tradition. (good ole intellectual humility)]
Analogous to how Engineers often find it more profitable to mimic the mechanisms that nature has developed through evolution, than to think up novel mechanisms from scratch.
So, as long as one retains rationalism / pragmatism as one’s guiding principle (epistemology / hermeneutic), then one may find that “God” and Science both in fact agree on the same kind of “objective” morality.
[“God” (religion) got there first, though one day Science might catch up and exceed “God”. Actually, that’s somewhat a false dichotomy …]
Bonus: One key feature I find in biblical morality has to do with the simple contrast between short-term good and long-term prosperity; the morally upright way being the one that optimises long-term wellbeing.
For now, I’ll leave the rest of the story to Jordan Peterson’s capable hands.
Caveat Lector 
Or try a parent-child relationship. It is wise for a small child to obey his parent’s instructions, because even if the child is unable to understand the parent’s explanation for why the instruction should be obeyed (interestingly, even if the parent themself is unable to properly articulate a reason), the mere fact that the parent has survived for many years, is good reason for obedience. As a child grows older and more intelligent, he may begin to see more and more the wisdom embedded in his parent’s instructions. One day when his experience and intelligence exceeds that of his parent, he can decided that his parent’s instructions are no longer optimal, and come up with his own superior set of instructions.
So in our modern-day concern of Religion vs Science, the question is whether our science is sufficiently sophisticated enough to completely abandon religion. The answer is often somewhere in-between.
A very young child obeys his parent blindly. A mature adult no longer heeds his parent’s instruction (but may continue to act as though he were following many of the instructions, because rationally he can see why they are optimal). *An intellectually arrogant child may decide to stray from his parent’s instruction, without having established sufficient grounds to do so, and thereby suffer the negative consequences.
So Jordan Peterson thinks that human society is not ready to leave their parent religion (Christianity), while Sam Harris thinks the parent is too old and superstitious to be useful at all.
Is human society sufficiently mature to completely give up religion? Even if people like Sam Harris are intelligent enough to derive their own morality via purely rational, non-religious means, do you think the average person can do that? Would Sam Harris insist that the dumber people obey the moral imperatives given by the smarter people? Wouldn’t that be like a sort of religion in itself?
[My personal opinion is that teaching critical thinking is the real priority. It is far more important that people learn to properly think, than to be force-fed the right things to believe. Atheism by itself doesn’t solve anything if its adherents also function under a fundamentalist epistemology and just happen to begin from a set of non-theistic axioms.]
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