2 Corinthians 11:12-15

But what I am doing I will continue to do, so that I may cut off opportunity from those who desire an opportunity to be regarded just as we are in the matter about which they are boasting. For such men are false apostles, deceitful workers, disguising themselves as apostles of Christ. No wonder, for even Satan disguises himself as an angel of light. Therefore it is not surprising if his servants also disguise themselves as servants of righteousness, whose end will be according to their deeds.