I hated the gathering of evildoers, and I did not sit with the wicked.
MIDRASH TEHILLIM
1.....(26.4) I hated the gathering of evildoers...
What assembly of evildoers?
The one which it is said: "the people gathered to Aaron" (Shemot - Exodus 32:1) at the making of the molten calf.
And also the one of which it is said: "Korah assembled all the congregation against them..." (Bamidbar - Numbers 16:19).
Rabbi HIRSCH
1. I hated the gathering of evildoers...
There is no moral or social evil that does not appear less brutal in the eyes of the world once it has become widespread among larger circles. That which an individual would not take the liberty of doing himself seems unobjectionable to him once it has become a general practice and is advocated by a (KAHAL) - "community.”
“But as for me,” David says of himself, “I hate evil, even if it be slavishly followed by an entire (KAHAL), and I renounce both my seat and my voice among those who will not pay God's Law the tribute due it."