A famous Bible teacher once cast out an evil spirit from a woman, and immediately after that her dog jumped off from a truck and died. He assumed that the woman had 'a spirit of suicide' and that it had entered into the dog from her. This 'taught' him that henceforth whenever he cast out a demon he should pray for the protection of the relatives of the person from that demon entering them.
We may have come across a few or more cases where a family has a series of calamities happening to them, and then someone tells them that this is due to witchcraft or black magic which someone has done against them.
We are expected to learn from our experiences as a means of growing in knowledge and wisdom. We can learn from our own experiences and from watching others. But if we 'learn' as in the above cases, we go entirely wrong. We may not only assume many things in error but we may also pass on such things to others. In that way we may become instruments in the hands of the Deceiver.
What we need to do is to interpret experiences in the light of God's word. It is very clear from the Bible that evil spirits cannot touch God's people because they need permission from God to do so (Job.1:10). Evil spirits need permission even to enter pigs (Lk.8:32). Why should we live in fear that some evil spirit will proceed from some relative and jump on us? We too should be careful against evil spirits getting access to our life avoiding continuing in sin (e.g., Ep.4:26,27), indulging in occult Satanic activities, or worshipping idols (behind whom are demons 1Co.10:20).
Don't we know that God is now our Father and that it is His responsibility to protect us? The Bible says that witchcraft or black magic will not work against us because we are His children (Nu.23:23) and not even curses will have power over us because we are under the blessing of God (Nu.22:12;Ga.3:13,14). Why do we live in fear of evil spirits or calamities? Is it not because we do not believe what the word of God tells us?
So we see that whenever we try to understand some experience, we must go to the word of God to see what God has to say about such things. When God says something, let us hold on to it, even if we are unable at the moment to explain what we have seen or experienced. If we stay with God and His word, He may give us an explanation sooner or later when we have become mature enough to understand His ways.
We must remember that we cannot explain a college level subject to a primary school student. We have to wait till he gets to college. So depending on our level of understanding we may be able to understand certain things of God. But we can believe God even when we cannot understand things. Even if our experiences seem to point to some conclusion which is contrary to the word of God, it is right for us to stay with what God has said.
We may never fully understand certain things of this life, but we can always trust in our Father and His word.