Why does it say "Atah Sakum"?
Radak: This is like one who rises from his place and is aroused to act. The same applies to "Atah Akum Yomar Hashem" (12:6).
Malbim: Even though I will not live forever, You do; You will save Tziyon.
Why does it say "Terachem Tziyon"?
Radak: It was desolate for many years. I know that You will have mercy on it. We know that You will have mercy on it, build it and desire it.
Malbim: This is one of the three reasons why You will save Tziyon - mercy on its affliction and lowliness. Also refer to 102:14:3:3, 104:14:4:2.
Why is this the time to have grace on Tziyon?
Rashi: You promised "Ki Yir'eh Ki Azlas Yad" (Devarim 32:36) - this was fulfilled.
Radak: A time will come that You will have grace on Tziyon, even though You were very angry at it.
Malbim: There are special times of Ratzon, for grace on those who do not deserve it.
Why does it say "Ki Va Mo'ed"?
Radak: There is a fixed time for Ge'ulah. When the time will come that You will have grace on it, they will say that the time came for Ge'ulah.
Malbim: If Tziyon will not be saved before the time via mercy or a time of Ratzon, it must be saved when comes the final deadline that the Nevi'im discussed. earlier - "b'Es Ratzon Anisicha uv'Yom Yeshu'ah Azarticha" (Yeshayah 49:8).
