Revelation 2:14-16

But I have a few things against you: you have some there who hold the teaching of Balaam, who taught Balak to put a stumbling block before the sons of Israel, so that they might eat food sacrificed to idols and practice sexual immorality. So also you have some who hold the teaching of the Nicolaitans. Therefore repent. If not, I will come to you soon and war against them with the sword of my mouth.