But you have this in your favor: You hate the practices of the Nicolaitans, which I also hate. - Revelation 2:6
We are taught things and all around us others are taught the same things so we are not prone to question is it right what we are believing. For many Bible passages this happens where there is an modern accepted definition and to question it makes you seem almost rebellious against others. Seldom many go past what they heard to research that possibly early believers thought of this passage and doctrine. The early Church Fathers at times help us understand some of these terms that we would simply have to guess otherwise at the meaning. Many modern believers take the word etymology of Nicolaitans, Nico meaning "victory" and Laitans meaning "people." In short, the modern belief by some is that the doctrine was the separation of special clergy above normal believers, and that those clergy controlled and ruled over them. Many who hold to this view that God hates such things are usually in modern autonomous evangelical assemblies who feel any leadership over a group of local churches is wrong.
We get a much different picture when we delve into Church history. It was commonly held amongst many of the early church leaders that the Nicolaitans were followers of the deacon Nicolas of Antioch (Acts 6:5) who ended up teaching wrong doctrines. Irenaeus said, "The Nicolaitanes are the followers of that Nicolas who was one of the seven first ordained to the diaconate by the apostles. They lead lives of unrestrained indulgence. The character of these men is very plainly pointed out in the Apocalypse of John, [when they are represented] as teaching that it is a matter of indifference to practice adultery, and to eat things sacrificed to idols." What is sobering to us in this is that Nicolas again was one of the specially chosen Deacons who were chosen by the Apostles before the Lord. Balaam also was a prophet of the Lord who erred and his doctrine and teachings are condemned in the the same practices as the Nicolaitans. We see in context that they were teaching to eat things sacrificed to idols and to commit fornication (Revelation 2:14-15). Interestingly, these were the chief matters condemned by the decree of the Apostolic council (Acts 15:29). So we see a much different picture from early Church history and namely the Book of Acts. It also paints for us a very sobering account of an early Bishop of the Church apostatizing into false doctrines that the Lord hated. May God keep us away from such errors and to confess and follow the faith once given to the saints (Jude 1:3).