God makes use of vessels to do his work. Sometimes these are righteous vessels (like Isaiah), and sometimes these are wicked vessels (like Nebuchadnezzar). Most times, however, they are a little righteous and a little wicked (like Gideon, who did some things right and some things wrong). The righteousness of a man does not indicate that anything he says is true. The Bible is full of examples of true messages from God being delivered by men who were not worthy of emulation. On the other hand, the wickedness of a man does not indicate that a particular belief he has is not from God. The high priest who killed Jesus delivered a true prophecy (see John 11:49-51)!
The Lord Jesus was and is the perfect conduit of truth. Everything he teaches provides increased light and truth for everyone he teaches. This is an exceptional position. The amount of light and truth you possess will determine the probability of encountering more in someone else. Those with a normal amount—that is, very little—have a good chance of learning something from everyone they meet. Even in this case, this doesn’t mean that everything others believe represents incremental truth to you. Almost everyone you encounter will possess a mix of beliefs that represent increases in truth for you and beliefs that are lower than the truth you already possess. Some few people you encounter—and the more truth you have, the fewer they will be—will possess more truth than you on all or almost all subjects.
When we encounter anyone who has more light and truth than we do, our objective is to obtain all they have, become as close to God as they are, and then go find more light and truth elsewhere.
Unfortunately, this rarely happens. Most people are incredibly naive and will fall for any clown claiming spiritual experiences. Others are more discerning, but make a man their connection to God when they have validated some of his experiences and/or teachings. This latter case is common in the Bible, where on various occasions men would attach themselves to some prophet. These “schools of the prophets” are interesting. Can you recall the name of even one member of them, or one work they did? You can't, despite the fact that you can name the prophets: Isaiah, Jeremiah, etc. You see, content with making a man their idol, these people never ascended to connecting directly to God. Exceptions include Joshua, who created his own connection with God independent of Moses, and Elisha, who did the same independent of Elijah.
Please do not be so simple and foolish as to believe a man's message is correct just because he has had experiences with God. He could be a liar. He could be wrong. He could be clinging to lower truth. He could even be sent from God to lie to you. We ought to focus on the Lord Jesus, and scrutinize what we hear from men no matter what they have revealed or how beneficial it has been in the past.
Some people have had authentic experiences in the past, but have lost that light to the point where they cannot reproduce equal experiences in themselves, let alone instruct others on how to do so. This happens more frequently than I think people realize. If God visited you years ago, and never since, you really ought to humble yourself to the dust and ask him why. Spiritual experiences are meant to happen more frequently over time as one draws closer to God, not less frequently.
Do not assume that every spiritual experience comes from God. We seem to forget that Satan—the master counterfeiter—is always chomping at the bit to derail people. He is especially interested in derailing those who have been most successful in obtaining God. God only allows him to deceive to the degree that a person has the capacity to detect and withstand his deception. What this means is that those who have experienced the most are also the most likely to be deceived, because they are subjected to the greatest deceptive tactics.
Of particular vulnerability are those that haven't had an experience with God in a long time. Perhaps they slip into sin, or idleness, or pride, and have offended God but are unaware. Perhaps they are aware, but want both the fleeting pleasure of their sin and the peace that comes from a relationship with God. Of course, those can't co-exist. In any case, those more concerned with obtaining spiritual experiences than obtaining the reconciliation with God that generates them will find Satan all too willing to answer their pleas for spiritual experiences without the prerequisite repentance.
Walking the straight and narrow is a continuous experience. You have to consistently unlearn what you thought you knew and walk away from others who you thought were interested in knowing God the same way you were. Having one or many spiritual encounters in the past means nothing about your present standing with God. Like a fish, the only disciple that stays still is a dead one.
Always remember that a person can convey both truth and falsehood. Satan himself sometimes teaches truth in spite of it being surrounded by falsehood. When he told Adam and Eve that eating the fruit of knowledge would not kill them, which was a lie, he also told them it would give them understanding of good and evil, which was true. Men can likewise teach both true things and false things. A man's having taught truth in the past does not certify that whatever he teaches in the future will be true, and a man's having taught falsehood in the past does not certify that whatever he teaches in the future will be false.
Assuming one of worldly renown or one with spiritual experiences is right is trusting in the arm of the flesh.
Human beings love gurus. After all, it is much easier to decide whether a person is a so-called true messenger—a single, one-time decision—than it is to evaluate each teaching they offer independent from past experience.
Mortality is a dangerous place. A principle purpose of our being here is to learn to discern between good and evil. If it were as simple as identifying a person to whom we can attach ourselves to be saved, many more people would be saved. Instead, we are adrift and constantly bump up against putative truth. Most of it will be false, some of it will be true.
Most messengers will be completely false, and some few only a little false. There are plenty of examples of people who had one or two good ideas, or good ideas for a time, then veered off the rails.
When we believe that men's authority is required to save us, we set up certain individuals with dominion over us. We trust that whatever they tell us is God's word, and whatever they tell us to do is God's will. They become the source of truth for us. This is abominable idolatry. No matter what stature the idols have achieved with God, it can never bring you more than the glory of angels in the best case. In the worst case, it will lead you straight to hell.
Don’t outsource your relationship with God. It doesn't work like that. Salvation can only come through your personal relationship with God. You don't have the option of being saved in some other way. You can’t expect the awareness of others to translate into your knowledge. No matter what another person does, you still have to acquire light and truth for yourself in order to be saved.