1)
What is the meaning of "Chiyisani"?
1.
Radak: You separated me [from those who descend to Gehinom].
2)
What is "mi'Yardei Vor"?
1.
Rashi: This is like me'Yeridasi l'Vor, that I will not descend to Gehinom.
3)
Is "Chiyisani mi'Yardei Vor" a repetition of "He'elisa Min She'ol Nafshi"?
1.
Yes; Verses often repeat matters in different words. (Radak says so many times - PF)
2.
Malbim: No. My Nefesh was mortally ill due to sins. Via this, also the body fell ill. Via Your pardon my Nefesh will not descend and perish, and through this I also attained physical life. This is like "ha'Sole'ach l'Chol Avonaichi ha'Rofei l'Chol Tachalu'aichi" (103:3).
