Who were the Ratzim ha'Nitzavim Alav?
Rashi (citing Yerushalmi Sanhedrin 10:2: They were Avner and Amasa.
Radak: According to the Drashah that Avner and Amasa did not want to kill them (refer to 22:17:3:1), it is as if says la'Ratzim vela'Nitzavim. Avner and Amasa were officers, and not Ratzim!
How did the [other] Kohanim help David?
Malbim: At the least, they knew that he was fleeing me. They should have told me (Sha'ul)!
Why did they not want to strike them?
Rashi (from Sanhedrin 49a): They expounded "Ach" and "Rak" (exclusions) - "Kol Asher Yamreh Es Picha... Rak Chazak ve'Ematz" (Yehoshua 1:18) excludes a command of the king contrary to Torah (one must not obey it), Malbim - they [also] understood that [the accusation] was false.
