Note the mention of the Nicolaitans (Revelation 2:15) in close association with Balaam (Revelation 2:14). The two names, Nicolaitans and Balaam, have very similar meanings in their respective languages: “Balaam is derived from two Hebrew words, בָּלַע [bālaʿ] (‘he swallows’) and עָם [ʿām] (‘people’). Interestingly, according to the derivative meanings of the names, the two groups troubling this church [Pergamos] were ‘swallowers of the people’ (i.e., the Balaamites) and ‘conquerors of the people’ (i.e., the Nicolaitans).” If the similar meaning of their names is significant and if the fact that they are mentioned in neighboring verses in the letter to Pergamos is intended to show a relationship, then it has been concluded that the immoral impious teachings of the Nicolaitans might be understood in light of the doctrine of Balaam.
Revelation 2:14-15 tells us that those “that hold the doctrine of Balaam” (Rev. 2:14) are evidently identical with those “that hold the doctrine of the Nicolaitans” (Rev. 2:15). According to the best etymology, his name [Balaam], signifies “Destroyer of the people” ( . . . from בֶלַע [ḇelaʿ] and עָם [ʿām] ; and Νικόλαος [Nikolaos] (νικα῀ν τὸν λαόν [nikan ton laon] ) is the Greek version of this name. The Nicolaitans are the Balaamites. The sin of Balaam as committed in the Old Testament is now and has been for centuries, repeated as keeping the doctrine of the Nicolaitans – a tactic of the Adversary to destroy the people of God using the same temptations whereby Balaam had sought to overcome them centuries ago.
The Moabite King Balaak hired Balaam (Numbers 22:5, Deuteronomy 23:4) to curse Israel, which he failed at (Numbers 24:1). A plan was hatched whereas Israel would be lured into sexual relationships with the women of Moab (Numbers 25:1; Numbers 31:16) which would also entice them to worship foreign gods (Numbers 25:2). The key was to be intermarriage with the heathen leading to compromise and idolatrous worship. Peter mentions false teachers who are following the way of Balaam: “These people have left the straight way and wandered off to follow the way of Bil'am Ben-B'or, who loved the wages of doing harm” (2 Peter 2:15). Peter said that using deceitfulness these teachers will exploit the church: “But among the people there were also false prophets, just as there will be false teachers among you. Under false pretenses they will introduce destructive heresies, even denying the Master who bought them, and thus bring on themselves swift destruction. Many will follow their debaucheries; and because of them, the true Way will be maligned. In their greed they will exploit you with fabricated stories. Their punishment, decreed long ago, is not idle; their destruction is not asleep!” (2 Peter 2:1-5). Peter explains: “…especially those who follow their old natures in lust for filth and who despise authority. Presumptuous and self-willed, these false teachers do not tremble at insulting angelic beings;” (2 Peter 2:10) and “they have eyes always on the lookout for a woman who will commit adultery, eyes that never stop sinning; and they have a heart that has exercised itself in greed; so that they seduce unstable people. What a cursed brood!” (2 Peter 2:14).
This matches the libertine (a person, especially a man, who behaves without moral principles or a sense of responsibility, especially in sexual matters) aspect of the Nicolaitans mentioned by the early historical witnesses, Irenaeus, Hippolytus, Clement, etc. It is said that Balaam taught Balaak to influence the Israelites “to eat things sacrificed to idols, and to commit sexual immorality” (Revelation 2:14). How similar this is to the warning given the Gentiles by the Jerusalem council:
Therefore I judge that we should not trouble those from among the Gentiles who are turning to God, but that we write to them to abstain from things polluted by idols, from sexual immorality, from things strangled, and from blood. (Acts 15:19-20)
Both passages connect eating meat sacrificed to idols and sexual immorality.