Begging the question, also known as a circular argument, is a logical fallacy that has the conclusion included in the supporting premise.
For Example:
We know the Bible is real because God wrote the bible and God never lies.
If the Bible is real then that means God wrote it. So we could replace the first part of the sentence with, “We know God wrote the Bible because God wrote the bible and God never lies”. It’s a little more clear now how this argument is circular.