1)
From what should Hashem release him?
1.
Radak: Their evil words should not harm me.
2)
Why does it say "me'Ish Chamasim Tintzereni"?
1.
Radak: This repeats the start of the verse in different words.
2.
Malbim: There are two kinds of pursuers. (a) Some seek to harm without any benefit for themselves - they covertly slandered David. This is "me'Adam Ra...; Asher Chashvu Ra'os b'Lev" (3). (b) Some seek to extort him for their own benefit. They openly fought him - "me'Ish Chamasim Tintzereni; ... Kol Yom Yaguru Milchamos" (3).
