On what authority?

So what your pastor speaks about is not probably exactly the same as the pastor that is down the street or around the corner. Huh? So who is correct? Because someone has to be.  God is a God of truth and absolutes. God is not vague. Where do these people get their information? The Bible says that the Spirit will guide you into all truth, but everyone has different truths, so that cannot possibly be right. Right? I'm glad to know that there is a structure in place already that is guiding me. Through the Holy Spirit of course and it does not contradict itself.