The claim: The Bible says that God exists. The Bible is the inspired word of God, therefore whatever it says must be true.
The flaw: Circularity. God exists because the Bible says so, and we should trust the Bible because it is the word of God. This argument assumes the very thing (God) we are trying to prove. The same argument and logic can be used for any text that is considered revelatory--the Quran, the Torah, the Book of Mormon, or anything else.
The claim: The presence of miracles points to a supernatural force or god; miracles do occur, therefore there is a supernatural force or god
The flaw: The fact that miracles exist does not prove that they were caused by God (they could have been caused by an ancestor spirit). Thus this argument commits the fallacy of begging the question--it assumes that which is to be proven.
Separately, it is impossible to prove that miracles occur because in order to prove that an event occurs, you must use the laws of nature, but miracles by definition are violations of the laws of nature.