From Acts 27 it is clear that you should always listen to someone who is in communion with God. But even if you don’t God can still be merciful if that godly man (or woman) intercedes on your behalf.
This passage is one of the few in Scripture which shows an example of a man apparently changing God’s mind on something. In Acts 27:10 Paul predicts that their lives will be lost along with the cargo and ship whereas in v.22 he predicts that there will be no loss of life, which is how it turned out. In between v. 10 and v. 22 Paul had been praying and God had heard and answered his prayers and effectively had changed His mind.
The most famous example of this is when Moses interceded on behalf of the people of Israel in Exodus 32: 9-14. What both examples (and others) show is that we are not dealing with some immovable stone image or machine that churns out decisions from on high that cannot be changed. This is the opposite of determinism and causes no end of theological conundrums for anyone approaching God without knowing Him. We reach the limits of rational thought in this kind of thing.
Recently I was sharing with an engineer at work, a clever guy. He started the conversation by asking how I could logically think that the bible could be right about God. After some useful debate (which I must put in another blog) I ended up by saying that God reaches everyone not just the logical. And He does it by summing everything up in two promises: You shall love the Lord your God with all your heart and all your soul and all your mind and all your strength and your neighbour as yourself.
Thankfully we are not limited to being rational when dealing with God. Let’s be rational, but more than that, let’s be in love.