Revelation 2:15

Overview - Revelation 2
What is commanded to be written to the angels, that is, the ministers of the churches of Ephesus,
12 Pergamos,
18 Thyatira, and what is commended or found wanting in them.
Treasury of Scripture Knowledge

Revelation 2:15  (King James Version)
So hast thou also them that hold the doctrine of the Nicolaitans, which thing I hate.

the doctrine