I was asked the following question which gave me pause to think about this..
"Do you believe that people will still have dreams and visions from God today?"
We know what the Bible says will happen at the end..
Joel 2:28
And it shall come to
pass afterward, that I will
pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions:
Acts 2:17
And it shall come to pass
in the last days, saith God, I will
pour out of
my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams:
We seemed to have gotten a slew of people lately saying they have had dreams and visions from God and most have turned out to be false or worse, teaching doctrines of demons. So how will the Holy Spirit be poured out in the end times if not in dreams and visions, and how will they know if it is truly the Holy Spirit versus a unclean or evil spirit.
This is the sort of thing that falls very nicely under "test all things, hold fast what is true".
Some people say God will never contradict his word. That's not entirely true - Ezekiel was told to cook food using human waste and cut his beard, both in direct violation of the Mosaic law. But anything that appears to contradict God's word should be handled very carefully and it's probably best to assume it's false unless it can be verified first.
Dreams and visions can sometimes be tricky because they are so personal, nobody can verify what dream I had or didn't have and many times all we can do is weigh it, consider it, and then make a decision whether to act on it. That leads to another area of great caution.
If I have a dream that suggests I should take action it's up to me whether I take the action, and the consequences are mine to own. If I have a dream that suggests you should take action, what responsibility am I willing to accept if you take the action and it all blows up in your face? If my response is likely to be little more than a shrug and "sucks to be you", be careful. If I truly believe my dream is from God I should be willing to accept at least some responsibility if it goes sideways. If God is truly using my dream to speak to you the chances are it will confirm what you are already thinking, or what unrelated people have said to you. If it comes completely out of left field, it might be the first of many things that point the same way or it might be an outlier, so be careful. Also consider how it's presented - is it presented in a spirit of humility, along the lines of "I had a dream and I think God might be trying to say....", or more along the lines of "I had a dream and God is telling you to....". The person who uses lines like "you're not arguing with me, you're arguing with God" when what they present is a dream is something worth treating with caution.
I don't see anything wrong with asking for verification if something suggests making a major change.
To give a couple of examples - many years ago I had a dream that I was walking down an alley near where I lived and saw a young woman begging, I gave her a coin, and she smiled at me as she thanked me. The very next day I happened to be walking down that exact alley, I saw a young woman begging, and I had the exact denomination coin I dreamed of. So I gave her the coin, she smiled at me as she thanked me, and I went on my way. The coin in question was equivalent to about 80 cents so, even though this was over 30 years ago, it's not like the consequences either way were significant. If the dream was just some random stuff from my mind, I was down less than a dollar. If that coin made a lasting difference to the young woman's life then all well and good (it's hard to see how 80 cents would make much difference but sometimes it's the gesture rather than the amount).
In the last 15 years or so my wife and I have made two very substantial life changes, both of which were initiated by circumstances we didn't expect but also where everything aligned. In these cases we spent a lot of time considering, praying, and seeing if everything aligned before we made major decisions. These were things that would have had a massive impact had we "got it wrong", so we wanted to make sure we were happy with the consequences of a decision before we stepped out.
The trouble with anything relating to a personal calling is that you'll never find a single verse in Scripture that confirms it. You might find verses that falsify it - to take a silly example if someone says God is calling them to start an affair we don't have to look very far in Scripture to find a verse that says otherwise. But if you feel God is calling you to be a missionary to Mozambique, or to leave your job as a doctor and become a teacher, you won't find a verse anywhere that tells you yes or no. You can find a verse that indicates it might be valid - Jesus said "go into the world" but that doesn't tell you whether "the world" for you means Main Street in your home town or Mozambique. James says that pure and undefiled religion is to look after widows and orphans but that doesn't mean that you or I specifically should quit our jobs and open an orphanage.
We can study Scripture and see the kind of situations God called people into, and see whether our dream or vision is consistent with the overall pattern. We can ask for validation, depending on how significant the calling appears to be. And sometimes we can do little more than either reject it, or take a breath and jump in with both feet.