Revelation 2:14-15

14But I have a few things against you, because you have there some [among you] who are holding to the [corrupt] teaching of Balaam, who taught Balak to put a stumbling block before the sons of Israel, [enticing them] to eat things that had been sacrificed to idols and to commit [acts of sexual] immorality.

15You also have some who in the same way are holding to the teaching of the Nicolaitans.