2 Corinthians 11:12-15

But what I am doing I will keep doing, [for I am determined to keep this independence] in order to cut off the claim of those who want an opportunity to be regarded just as we are in the things they brag about. For such men are counterfeit apostles, deceitful workers, masquerading as apostles of Christ. And no wonder, since Satan himself masquerades as an angel of light. So it is no great surprise if his servants also masquerade as servants of righteousness, but their end will correspond with their deeds.