Where did Hashem say so?
Rashi: He said so in His heart.
Radak: Until now, I said that I will sustain (return) you in the end of days. If you want, you need not be exiled. I said that you are My children - "Banim Atem la'Shem Elokeichem" (Devarim 14:1).
What is the meaning of "Eich Ashisech ba'Banim"?
Rashi: How will I put My congregation and nation among other sons, mixed among the nations?! Therefore I chose for them a nice portion, and gave to them a choice land.
Malbim: This is a parable for one who had a beloved daughter among many sons, and he feared to house her among them, lest they do evil to her or make her go to bad deeds. Therefore he gave to her an inheritance of a special field and vineyard. Hashem did not want Yisrael to mix with Goyim, therefore he gave to her a precious land.
What is the meaning of "[Nachalas] Tzvi [Tzeva'os Goyim]"?
Rashi: It is an inheritance, the desire of all legions of Goyim. Radak - this is a repetition of Eretz Chemdah.
Malbim: It is an eternal inheritance.
Why did he say "Tikre'i Li Avi"?
Malbim: You will appreciate that I gave to you an eternal inheritance.
Why is it written Tikre'u, and we pronounce it Tikre'i?
Radak: It is pronounced singular, corresponding to Keneses Yisrael. It is written plural, corresponding to the nation. They are the same. The same applies to Tashuvi; it is written Tashuvu.