Why does it say "Lo Yitz'ak"?
Radak: Normally, a judge needs to scream at the litigants and force them to accept his verdict. He will not need to. He will speak gently, and they will accept his words.
Why does it say "v'Lo Yisa"?
Rashi: He will not raise his voice. He will not need to argue and have Nevu'ah for the nations. They themselves will come to learn from [Yisrael] - "Nelechah Imachem Ki Shamanu Elokim Imachem" (Zecharyah 8:23).
Radak: This is a repetition of "Lo Yitz'ak."
Malbim: Other Nevi'im used a metaphor to enter their words into the hearts of the listeners. He will not use metaphors.
Why does it say "v'Lo Yashmi'a ba'Chutz Kolo"?
Malbim: Other Nevi'im needed to stand outside and make their voices heard where the nation gathers. He will not need to do so.