Where on the Main C.SE site or Christianity Meta is the information discouraging just copying and pasting even when referencing the source?
If your answer is entirely a quote of another work and nothing else, then you should expect negative feedback, even if you sourced it.
If your answer copies the content from another source and does not note that source, then it is plagiarism, which is a serious offence in academic settings, which is exactly the setting we are going for here.
I consider this common sense for anyone who went to high school.
Plagiarism - posting the work of others with no indication that it is not your own
Do not copy the complete text of external sources; instead, use their words and ideas to support your own.