2 Corinthians 11:4, 12-15

For [you seem willing to allow it] if one comes and preaches another Jesus whom we have not preached, or if you receive a different spirit from the one you received, or a different gospel from the one you accepted. You tolerate all this beautifully [welcoming the deception].

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.