Applying Modus Tolens to unsupported claim

I'd say the logical form is closer to the following (let P be 'God' and Q be 'moral knowledge)

(1) If not-P , then  not-Q

(2) Q , therefore

(3) P

The argument is logically valid (no formal fallacy) but it's  unsound  because (1) has not been argued for. That's the name for these types of arguments - they're unsound (rationally unpersuasive) because of the dubious initial premise.

For starters, 'God' is not defined so we don't know which cosmic entity the speaker is referring to.

There's also a chicken-or-egg problem as far as moral knowledge is concerned. Is something moral because God approves of it? Or does God approve of it because it's moral? If the former, then plausibly, God could approve of psychopathic acts like mass murder, and we would be compelled to commit these. If the latter, then God seems redundant, as his approval is after-the-fact.

[To TrappedPrior (RotE)]

+1 for tipping me about "unsound" arguments. I didn't know that term. Thanks!
Also from the answers given so far I deem your answer (an unsound argument) to be the most valid answer to my question. As I wrote in my comment to the AI-guy, I don't see it as non-sequitur or begging-the-question type, just an an unsupported claim with a fancy ribbon around it to make it look like a valid argument. Arguments like these are a dime a dozen.

As for the 'God' definition, it doesn't matter. The person who made that argument could pick any definition they think it suits the argument better as far as I'm concerned; it doesn't matter cause it doesn't change the validity of the argument. That's why I gave the second example. What both arguments demonstrate is how one can create unsound but somewhat valid-looking arguments from an arbitrary unsupported claim. I wasn't trying to argue anything related to moral knowledge, I wanted to only examine the form of such arguments. 

Thank you Kaiden for your answer! It wasn't very clear to me the term "valid". I used to think that something is valid as being sound, I didn't know the particular terminology used in logic.
With your answer you clarified what the "validity" and TrappedPrior (RotE) with his comment clarified what the term "sound" means - in the meantime I also looked it up in some videos - but thanks! 

To reiterate, the only kind of premise that can make an argument unsound is a  false  one. I’ll leave it at that, and you are welcome! 

Thank you for your answer. I agree with the false premise (which I also state in my initial post). I don't see how it may be a "Begging the question" since I don't see how the conclusion is implied in the premise. The premise does not assume the existence of God. It assumes that without a god we can't have moral knowledge. The premise just states a consequence of the existence (or non-existence) of something. It does not assume the existence. Also, since the reasoning is valid (modus tollens) it can't be non-sequitur, (if the premise was valid, the argument would be valid). So it's just false premise.

So, my question is if there is a specific name for that specific way of constructing invalid arguments using modus-tollens from false premises.

Also, another question I have for a while is, are your answers AI-generated, and if so from which software?

Thank you for the answer but my question was not about how rational the argument is, or whether the initial premise is valid or not. My question was if there is a known name for creating such modus tollens arguments from arbitrary claims - something more specific and precise than the generic False Premise or Non-sequitur.

Ah, yes, you are right. I read it too fast and misunderstood. Sorry about that.

Ah, no worries man, I've been there too ;)