Why do they not know the path of Shalom?
Radak: They never went on it.
Malbim: Derech is the great path fixed for the Rabim. The Rabim who have Mishpat and etiquette go on the path of Shalom - a conduct that guards Shalom among a society, that people not oppress each other. They do not know this path.
What is the meaning of "v'Ein Mishpat b'Magelosam"?
Rashi: In the circuit of their ways, nothing is judged truthfully.
Malbim: Ma'agal is a circular path. Also a company of murderers and thieves, even though they do not follow the great path for the Rabim, they have Mishpat among themselves etiquette and conduct that guards straightness within their group. E.g. they have protocols how to divide spoils, and how their partnership works. They lack this even within themselves.
Why does it say "Nesivoseihem Ikeshu Lahem"?
Rashi: They made the paths crooked for themselves [Radak - and they stumble on them].
Malbim: Nesiv is a private path. The individuals do not have even private paths of Shalom; everyone troubles his relatives and destroys his household and himself.
