What is the meaning of "Lo l'Shalom Yedaberu"?
Radak: This is like "v'Lo Yachlu Dabro l'Shalom" (Bereishis 37:4; they could not speak peaceably).
Malbim (20-21): False slanderers normally distance their words - 'I heard from Ploni and Almoni, who already died.' Since they did not speak Shalom, they plotted words of guile on Rig'ei Aretz, i.e. they attributed them to the dead, who are in graves. Afterwards, they were brazen to strengthen their words, and say that they themselves saw David do so - "va'Yarchivu Alai Pihem" (verse 21).
What are "Rig'ei Aretz"?
Rashi: They are the cleavages 1 of the land. The same applies to "Roga ha'Yam" (Yirmeyah 31:34).
Radak #1: It is like Margo'a (serenity); these are the humble of the land. The humble are soft and acquiescent.
Radak #2: They are the fat and calm, who have serenity. "V'Al" is like v'Im (with). The same applies to "va'Yavo'u ha'Anashim Al ha'Nashim"(Shemos 35:22). These flatterers and mockers, together with the fat and serene Resha'im, plot schemes about me. They are comfortable, and I am exiled and afflicted!
Radak: I.e. in hidden places. This is wrong. One does not need a hidden place for thoughts, only for speech or action! (Perhaps indeed, they discuss their evil thoughts, and how to fulfill their schemes! - PF)
