I agree, Jordan Peterson is a very smart man and his approach is definitely different than 99.9% of believers on why they believe in what they believe. For example, he does ''believe'' in evolution unlike your friend badecker and he is definitely a hardcore christian, if only every religious person was like him the world would be a better place. However asserting that morality comes from an outside source without proof of any outside source or even that it is an external source and not an internal source without any proof of either is ludicrous. I will point out that it was society and not religion or your god that determined that slavery is immoral. This would indicate that morals are a construct of society and not a greater being that can't be proven.
It is important to seperate the message from the messenger. All messengers are potentially subject to error but if we can reconstruct the same ultimate message from a multitude of messengers regardless of their differences and starting positions and then we must carefully consider the message for it has proven itself robust.
Let's briefly look at some of the various messengers we have discussed in this thread.
Bruce Charlton approached religion through a metaphysical framework highlighting that all knowledge is ultimately reducible to basic and unproven axioms.
https://bitcointalk.org/index.php?topic=1373864.msg22344436#msg22344436Perry Marshall examined the axiom of God and showed us that it is not falsifiable.
https://bitcointalk.org/index.php?topic=1373864.msg23796852#msg23796852Dennis Prager explained how the axiom of God leads directly to the reality of freedom.
https://www.prageru.com/videos/i-am-lord-your-godMoshe Chaim Luzzatto shows how starting from the axiom of God one can understand free-will, the existence of evil, and why bad things sometimes happen to good people.
http://www.livingjudaism.com/the-way-of-god.html Jordan Peterson approaches the Bible from an perspective of evolutionary psychology and finds psychological truths.
https://m.youtube.com/watch?v=f-wWBGo6a2wWhat all of these vastly diverse approaches have in common is that they converge on is a single basic message.
God = True
This is the critical axiom the foundation that ultimately supported the rise of western civilization and the enlightenment.
If we can show that morality follows from acceptance of the axiom is that morality coming from an external or internal source? The very question is almost irrelevant answerable in either the affirmative, the negative or perhaps both.