Why is it written Yashuv, and we pronounce it "Yashiv"?
Radak: The Kesiv is Po'el Omed (the action applies only to the subject; the evil itself will return to them). The pronunciation is Hif'il (Hashem will return the evil to them).
Who are "Shorerai"?
Rashi: They are people who look to [Radak - harm] me. This is like "Ashurenu v'Lo Karov" (Bamidbar 24:17) (Radak - and "va'Yhi Sha'ul Oyen Es David" (Shmuel I, 18:9). So Zifim looked to David, to where he went, and told Sha'ul.)
Why did he say "ba'Amitecha"?
Rashi: Because You are truthful, and You said that You will punish slanderers and those who pursue to kill, cut them off.
Radak, Malbim: Your word to make me king is Emes. They seek to remove me from the world!
