A.T. Robertson Commentary Revelation 2:6

"But this thou hast, that thou hatest the works of the Nicolaitans, which I also hate." — Revelation 2:6 (ASV)

That thou hatest (οτ μισεις). Accusative object clause in apposition with τουτο (this). Trench tells of the words used in ancient Greek for hatred of evil (μισοπονηρια) and μισοπονηρος (hater of evil), neither of which occurs in the N.T., but which accurately describe the angel of the church in Ephesus.

Of the Nicolaitans (των Νικολαιτων). Mentioned again in verse 15 and really meant in verse 2. Irenaeus and Hippolytus take this sect to be followers of Nicolaus of Antioch, one of the seven deacons (Acts 6:5), a Jewish proselyte, who is said to have apostatized. There was such a sect in the second century (Tertullian), but whether descended from Nicolaus of Antioch is not certain, though possible (Lightfoot). It is even possible that the Balaamites of verse 14 were a variety of this same sect (verse 15).

Which I also hate (α καγω μισω). Christ himself hates the teachings and deeds of the Nicolaitans (α, not ους, deeds, not people), but the church in Pergamum tolerated them.