What has Yetzi'as Egypt got to do with the La'av of Ribis?
Rashi #1: To teach that, just as in Egypt prior to the Exodus, Hashem discerned the difference between a drop that was a Bechor and one that wasn't, so too, will He discern the person who lends his money to a Yisrael and claims that it belongs to a Nochri - and punish him.
Rashi #2: To remind us that Hashem took us out of Egypt on condition that we observe His Mitzvos, even if they are sometimes difficult to keep. 1
Why does the Torah insert giving Yisrael the Land of Cana'an here?
Rashi #1: Because Hashem gave it to us as a reward for keeping the Mitzvos.
Rashi #2: Refer to 25:38:3:1.
And why does it add "Lih'yos lachem l'Elokim" here?
Rashi: With reference to the previous phrase, it teaches us that Hashem is the G-d of whoever lives in Eretz Yisrael, and that leaving Eretz Yisrael is akin to worshipping Avodah-Zarah.
Seforno: This is the main objective towards which one should strive, and it is best achieved by helping one another to ensure that communal life functions smoothly.