The not an answer flag reason reads
This was posted as an answer, but it does not attempt to answer the question. It should possibly be an edit, a comment, another question, or deleted altogether.
So, this flag should be used when the answer does not attempt to answer the question at all.
But the answer says where is the verse taken from and also the author of the verse and he also says it is not a part of any scripture. So, the answer attempts to answer by saying it is part of nothing. So, the Not An answer flag is not valid here. If the answer is wrong, it should be downvoted not flagged.
Just remember: if the text of the post contains an honest attempt at answering the question, then it is an answer - so don't flag it otherwise, and if you do, don't complain if your flag gets declined.
Read Your answer is in another castle: when is an answer not an answer? from main meta and also What to do with those type of questions whose answers are simple yes or no? from our meta.
Moreover, the other portions are not really adding anything after my this comment (which was posted much earlier than the answer)
Any useful information which attempts or tries to attempt the answer should go to answer section and not comments. Comments are for asking clarification or for suggesting informationComments are for asking clarification or for suggesting improvements. So, what you have put in the comment should be an answer actually.