What Casts Out Demons and Unclean Spirits: Prayer or Faith? Reading Matthew 17 #117

We face a seeming Bible contradiction today: Jesus tells the disciples they failed to cast an unclean spirit out because of a lack of faith in Matthew 17, but in Mark 9, He says they failed because of a lack of prayer. Does Matthew or Mark have it wrong? Actually, when we dig deeper, we see an amazing truth here, not a contradiction or error.