The bible says without faith you can not please God. You cannot prove God with a slide rule. I've heard the voice of the Holy Spirit twice and each time He was chastising me for wrong thinking. I've felt His presence of approval when I've done good things. I can't prove this to anyone else but I know He is real in my heart and He is part of the Godhead. I have faith in His word and what it says will come to pass. I can only tell others of my faith and belief, it is up to them to accept or reject. If I don't tell I can be held responsible for a person that is heading toward destruction, if I do tell and they will not listen, then I've done what is expected of me. The bible says do not cast your pearls before swine, sounds a bit harsh but true, some will never listen.