If we observe the miracles in churches today and compare them to the ones Jesus performed we would notice a very big difference.
In all the four Gospels that gives the accounts of the Miracles Jesus performed there is no where he asked those that have received a Miracle to come forward and give testimony in front of a gathering before he starts preaching the Good News to them or Jesus telling the people that at one of His previous gatherings some people got healed. The Miracles of Jesus were unique in that people knew the people in public before and after they have been healed, but today's miracles are not so.

This is the reason Jesus has warned we the elect with these verses:

Mark 13:22
22 For false messiahs and false prophets will appear and perform signs and wonders to deceive, if possible, even the elect.
23 So be on your guard; I have told you everything ahead of time.

Matthew 7:22 - 23
22 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?'
23 Then I will tell them plainly, ‘I never knew you. Away from me, you evildoer

Luke 18:8
8 "However, when the Son of Man comes, will he find faith on the earth?"