People who bring up the Holy Spirit as a means of justifying why they hold the true understanding of the Bible are in fact using circular reasoning:
The Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to... ad infinitum
The Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to the Holy Spirit described in the Bible tells me that the Bible which describes the Holy Spirit means this according to... ad infinitum
"It is the mark of an educated mind to be able to entertain a thought without accepting it" ~ Aristotle