Why does it say "Dabru Al Lev Yerushalayim" and "v'Kir'u Eleha"?
Malbim: Dabru Al Lev Yerushalayim corresponds to Ki Mal'ah Tzeva'ah; v'Kir'u Eleha corresponds to Nirtzah Avonah. If a long exile was decreed on someone, and he suffered his punishment according to the set time, one need not call him to return to his house. When the time finishes, he returns automatically. Rather, one must console him and speak to his heart for suffering so much, and nothing was pardoned. If via Chesed they pardoned his son before the time, one need not speak to his heart to console him, but one must call him, for he will not return by himself.
What is the meaning of "Ki Mal'ah Tzeva'ah"?
Rashi citing Targum Yonasan: In the future, it will be filled from the exiled nation. It is as if Ki Mal'ah mi'Tzeva'ah. Radak - Tzeva'ah is simply an army.
Rashi: Some say that Tzeva'ah is [time,] like "ha'Lo Tzava le'Enosh Alei Aretz" (Iyov 7:1). Radak - the time to be in Galus was completed.
What is "Nirtzah [Avonah]"?
Rashi: It was appeased.
Radak: Its punishment was completed. This is like "Az Tirtzeh ha'Aretz Es Shabesoseha" (Vayikra 26:34). "Avonah" is its punishment, like "Ki Lo Shalem Avon ha'Emori..." (Bereishis 15:16).
Radak citing Targum Yonasan: Its liability left it.
Malbim: [They will be redeemed earlier via] appeasement of their sin [via Teshuvah and merit].
Why does it say "Ki Lakchah mi'Yad Hashem Kiflayim b'Chol Chatoseha"?
Refer to 40:1:2:2.
Rashi citing Targum Yonasan: It received the cup of consolations from Hashem. It is as if it was stricken doubly for its sins.
Rashi: It received double punishment. What is the source? "V'Shilamti Rishonah Mishne Avonam v'Chatasam" (Yirmeyah 16:18).
Radak: Tichpal can be double or more, like "v'Sikafel Cherev Shelishisah" (Yechezkel 21:19). I.e. it will be doubled three times. Kiflayim means twice - the two times that Yisrael were exiled, to Bavel and this exile. This was due to Chol Chatoseha.
Radak citing Ibn Ezra: It was stricken twice as much as any nation.
Radak citing his father: It was stricken for their sins, and their fathers' sins - "Avoseinu Chat'u v'Einam va'Anachnu Avonoseihem Savalnu" (Eichah 5:7)
Malbim: [They will be redeemed earlier via] multiplication of their afflictions, until their punishment corresponds to all their sins. E.g. if one was sentenced to 10 years in jail and to receive 10 lashes each day, and the jail keeper lashed him 100 each day, he received the punishment for his sins in one year. He will go free [then]. So it was in Egypt. The harsh servitude completed the count of 400 years [decreed at Bris Bein ha'Besarim] in 210 years 1 .
Yisrael were in Egypt for 210 years. The servitude began only after "va'Yamas Yosef v'Chol Echav v'Chol ha'Dor ha'Hu" (Shemos 1:6). The Midrash says that the slavery was only 86 years, after Miryam was born. (PF)
