Jesus tells us that wisdom is vindicated by its works. We need to judge what is true not by what sounds good, but what this teaching or this person accomplishes for us and for others.
Based on Matthew 11:16-19
Jesus said to the crowds, ‘But to what will I compare this generation? It is like children sitting in the market-places and calling to one another,
“We played the flute for you, and you did not dance;
we wailed, and you did not mourn.”
For John came neither eating nor drinking, and they say, “He has a demon”; the Son of Man came eating and drinking, and they say, “Look, a glutton and a drunkard, a friend of tax-collectors and sinners!” Yet wisdom is vindicated by her deeds.’
(New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org)