Why does it say that he does not fear the great nation?
Radak: All of Yisrael were with Avshalom, except for those in Yerushalayim who left with him, and those who gathered to him afterwards.
Ba'al ha'Turim: It is because Hashem comes to save him. It says here "me'Rivevos", like "v'Asa me'Rivevos Kodesh" (Devarim 33:2).
Malbim: Had Achitofel's counsel been done, I would fear. Now that a great nation gathers around me to fight me, like Chushai's counsel, I do not fear.
What is the meaning of "Shasu"?
Rashi #1: It is an expression of She'iyah (destruction).
Rashi #2: This is like Samu (put), like "Lema'an Shisi Ososai" (Shemos 10:1). Radak #1 - they put their war against me.
Radak #2: They fought. This is like "Shasu ha'Sharah" (Yeshayah 22:7]. "Yashis bi'G'on Galecha" (Iyov 38:11).
