What is the question "ha'Shachach Chanus"?
Rashi #1: Did He forget to be gracious?! Chanus is the same grammatical form as Asos and Re'os.
Rashi #2: Chanus is like Chaninus (did He forget to pardon)?!
Radak: The mercy that He used to do - did He forget it?!
Malbim: Even though now we are not worthy of grace, we had grace earlier - "Zacharti Lach Chesed Ne'urayich" (Yirmeyah 2:2).
What is the meaning of "Im Kafatz b'Af Rachamav"?
Radak: This is like "v'Lo Sikpotz Es Yadecha" (Devarim 15:7). I.e. in His anger He closed His mercy, and will not open it to us again.
Malbim: He should have mercy when He looks at our oppression. Did anger close His mercy?! His way is to have mercy 1 !
Malbim: The verses mentioned five of His [13] Midos of Rachamim - Rachum, Chanun, Erech Apayim ("hal'Olamim Yiznach" - verse 8), v'Rav Chesed ("he'Afes la'Netzach Chasdo") and Emes ("Gamar Omer" - verse 9). The reasons to abandon us do not apply to Him - change of desire ("v'Lo Yosif Lirtzos Od"), not change of ability ("he'Afes