What is the comparison to slaves?
Radak: They are fed and financed only via their masters.
Why does it say "ch'Einei Avadim El Yad Adoneihem"?
Radak citing his father: When a master hits his slave, the slave lifts his eyes only to the master, to have mercy on him and cease hitting. So our eyes are only to Him to take us out of Galus.
Malbim: Sometimes the master's hand hits them, and sometimes it feeds them. So our eyes are to Hashem, who has mercy, whether He is Elokeinu, the Judge who rebukes and chastises,
Why does it mention also a Shifchah to her mistress?
Malbim: The mistress is not the primary influence; she receives from the master. Even so, the Shifchah's eyes are to her. So our eyes are to Hashem, whether we consider Him to be the Master who creates the good, or as a mistress who is an intermediary between the influencer and the receiver. So You are the first influence who creates the good, and You are Elokeinu who oversees us and hands the good to us.
Why is our verse in the [first person] plural? Verse 1 is in the singular!
Radak (1): Bnei Galus speak. Sometimes the singular is used, for the Klal, and sometimes the plural [for the individuals].
Why does it say "Ad she'Yechanenu"?
Malbim: Even though we are not worthy based on merits, do so amidst grace (an undeserved gift).