Rashi: Since they are obsessed with thoughts of ruses, they have no Simchah. People who counsel Shalom, they have Simchah.

R. Yonah: If someone counseled you to harm your colleague and take your vengeance against him, and he says that he is zealous for your honor, do not believe him. There is guile in the hearts of those who counsel evil. He did not counsel you amidst love, rather, amidst hatred of your colleague. If it was from love, he would not counsel to harm him and increase the latter's hatred of you! If you will do evil to him today, 'every person has his time' (Avos 4:3; he will have opportunity to retaliate). One hater should not be small in your eyes, and 1000 lovers should not seem much. Choreshei is an expression of counsel, like "Cheresh Leimor" (Yehoshua 2:1).

Malbim: Choreshei Ra is opposite Yo'atzei Shalom - "Oseh Shalom u'Vorei Ra" (Yeshayah 45:7). They want to annul the existence and destroy the pillars of civilization - Emes and Tzedek. They are like Ed Shekarim, evildoers and destroyers of the Klal and individual. They plot covertly, so no one will know; therefore, their hearts are full of deceit. They need to deceive so the congregation will not know and guard from them - "v'Ed Shekarim Mirmah" (17). They are always sad and full of worry lest their evil and deception become known - "v'Ad Argi'ah Leshon Shaker" (19). Evil is always sad; it cannot dwell with Simchah.

Rashi: Refer to 12:20:1:1.

R. Yonah: If someone counseled to make Shalom Bein Adam l'Chavero, both of them will love him. They will know that he has faithful love. One who conducts with this Midah, he will have many lovers and rejoice in them. Hatred of people breeds worry, and love of them breeds Simchah.

Malbim: Shalom makes the existence endure. It includes all good - of the house and the country. Counselors of Shalom love to benefit the Klal, and counsel to strengthen all good, straight and Tzedek. They advise based on Chachmah and Emes. Stam 'Etzah' is for good. He counsels openly. Tov is happy with his deeds.