If preachers were serious and open-minded
If preachers were serious and open-minded, they could have seen themselves as the object of Mathew 7:22-23 “Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name and in your name drive out demons and in your name perform many miracles?’ Then I will tell them plainly, ‘I never knew you. Away from me, you men of lawlessness!”
People who operate in the name of Jesus doing things such as preaching, casting out demons, or performing many miracles are called “men of lawlessness” (or “evildoers” in other translations) by Jesus himself.
Why? May be their motive is at fault (from God’s stand point of view)
But even from human point of view, miracle is needed when the message itself is too weak. That means if the message is true, it can stand on its own merit. Miracles actually do a disservice to the message itself.
This would also imply that Jesus too did not perform any miracles. Proof for this is not only what Jesus himself says in Mathew 7:22-23, but also results which the miracles produced. Jesus who said “Do not give what is holy to dogs, and do not throw pearls before swine” would not have given miraculous cures (what is holy) to unappreciative people. If he had given, it is natural that recipients of miraculous cures would have come in defense of Jesus when he was in trouble, or come for preaching work after his death. Yet none of them came!!!
If preachers were serious and open-minded, they wouldn't be preachers.