1)
Why did he say "v'Atah"?
1.
Radak: They hate me and speak bad about me. You should do with me for the sake of Your name in which I trusted!
2.
Malbim: You will do good with me for two reasons. (a) Due to Your name, which is called on me. You anointed me to be king, and there will be Chilul Hashem [if this is not fulfilled]. (b) Refer to 109:21:2:2.
2)
Why did he say "Ki Tov Chasdecha"?
1.
Radak: Your Chesed is good with everyone. It should be good with me, to save me!
2.
Malbim: This is a second reason to do good with me (refer to 109:21:1:2. Due to Your name, You should do with me wonders and benefit. In any case, save me due to Chesed!
