Ehrman is quite right when he says that Christian confusion over exactly what the Bible says belies the notion that the Holy Spirit lives inside Evangelicals acting as some sort of divine GPS or search engine. According to many Evangelicals, all they need to do is say, Lord lead me/show me the way, and BOOM! their lives follow the exact course mapped out by the Holy Spirit. The same goes for understanding the Bible. Evangelicals metaphorically type their questions into God’s Google app, and BOOM! the Holy Ghost leads them to the exact book/chapter/verse answer. Awesome, right? No need to think. Just “Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you, ” with God promising “every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.” (Matthew 7:7,8)
If the Holy Spirit lives inside EVERY believer, why can’t Christians even agree on the basics: salvation, baptism, communion, and whether masturbation is a sin. There are thousands of Christian sects, each guided by the Holy Spirit, each believing that their Jesus is the way, truth, and life and their little merry band of believers is the holder of the faith once delivered to the saints.