1)
What is "k'Imrasecha"?
1.
Radak #1: Like You promised.
2.
Radak #2: You said "Asher Ya'aseh Osam ha'Adam va'Chai Vahem" (Vayikra 18:5), and I do [Your Mitzvos]!
2)
Why did he say "v'Echyeh"?
1.
Radak: I will not die at the hands of evildoers.
3)
What is "mi'Sivri"?
1.
Radak: I hoped to You to save me from them.
2.
Malbim: It is my hope to do Mitzvos and good deeds, and not live a life of idleness. I do not consider this life!