You asked, who decides what's divine... the believer or the preacher?
Seems worded a little odd to me but I'll try to answer the best I can. We know the Divine when the Holy Spirit speaks to our heart and life and invites us to accept Jesus as our personal Savior. The Holy Spirit's role is to convict people of their sins so that they can come to Jesus and have him forgive them, which he readily does and turns no one away.
God's word helps us become familiar with him and know his ways. Ministers are also instruments of God and the Holy Spirit speaks to them about what to tell his congregation, so they can come to know Christ and why they need Jesus as their Savior. He tells you the right reasons why we need Jesus as our personal Savior. People just don't automatically know this and they
do not automatically have the Holy Spirit, until they repent of their sins and have Jesus forgive them. It's in the bible. There's no such thing as the Holy Spirit indwelling a vessel that is unclean before the Lord. Jesus sent out his disciples in the world and told them to tell people the good news of Salvation through Jesus Christ. This is important and that's what Believers today are called to do. The Bible says how will they know unless they are told?
I do not listen to man. His reasoning in itself and by itself is flawed. Therefore I listen to God who is sinless and I know will not lead me a stray in any way. Many people have many ideas on how to get to heaven but Jesus said there's only one way to heaven. He said that. Not me. I follow him and what he says. Jesus said if you listen to any other voice they will lead you astray. They definitely will. And those who followed Christ knew his voice and so they were able to tell others how to get to heaven. But one must be careful whom they listen to because some people think they're saved but they're not. They have not done as God has asked them to do nor followed his instruction. God said in his word that he specifically gave us his words so that we would know exactly how to get to heaven and not guess. The destination of our soul is definitely not something we want to guess about and where it's going to spend eternity. That's something we definitely need to get right, according to God's word. We can be stubborn about it and go our own way, certainly, but the Bible says
not all ways lead to Christ. There's a way that
seems right unto man, but the end thereof is death. Physical and spiritual death...Proverbs 14:12. God is telling us here, don't listen to just anyone who comes along. They may be following a path that they think is right but according to God, is not. Each person has to decide whether they're going to follow Christ or someone else. Christ is no liar, so that's why I trust him alone. If I thought for a second he was, I would not have followed him for a whole 52 years. He is definitely trustworthy.