1)
Why does He do the desire of those who fear Him?
1.
Radak: They call to Him in truth.
2)
Why does it say "v'Es Shav'asam Yishma"?
1.
Malbim: He saves them only after the cry for salvation. Here it discusses Yir'ei Hashem (verse 18). Those who love Hashem, He guards them (20), and no affliction comes upon them; they need not cry out.
3)
From what does He save them?
1.
Radak #1: From afflictions that come to the world.
2.
Radak #2: From afflictions that come to atone for their sins.