He didn't say if you had the gift you will lay hands on the sick and they will recover. If you "believe" in me you will. Also he says these signs follow those that Believe
2Th 2:6 And now ye know what withholdeth that he might be revealed in his time.
2Th 2:7 For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way.
2Th 2:8 And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming:
2Th 2:9 Even him, whose coming is after the working of Satan with all power and signs and lying wonders,
2Th 2:10 And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved.
2Th 2:11 And for this cause God shall send them strong delusion, that they should believe a lie:
2Th 2:12 That they all might be damned who believed not the truth, but had pleasure in unrighteousness.