Ramban and Seforno: To remind us that Hashem looks after those who keep the Mitzvos, that 'A Tzadik is not forsaken and his children seek bread!', ¹ as we saw in the desert, where Hashem sustained us (fed and clothed ² us - Seforno) with great miracles because we kept His Mitzvos.

Rashbam (in Pasuk 7): To remind Yisrael that success depends, not on one's own efforts and ability, but on the Chesed of Hashem - to counter what the Torah writes later, from Pasuk 7, that, when they come to Eretz Yisrael and everything goes well, they will become vain and forget Hashem. ³

Da'as Zekenim, Hadar Zekenim and Rosh: To counter the desire for the gold and silver on the idols - mentioned earlier, in above 7:25 - to remember how Hashem led them in the desert, where they did not need gold and silver.

Sha'arei Teshuvah (3:17): This is a Mitzvah to remember Hashem's Chasadim and to contemplate them - as the Torah writes in Pasuk 5 "Veyada'ata Im Levavecha".

Ramban ¹ : It refers to when they were forced to enter the desert ² without adequate provisions, where no food was available, and where, each day, all remaining Manna melted in the sun, and they were left yearning for the next fall the following day.

Rashbam, Seforno (on Pasuk 16): It refers to the fact that they never had any food for the next day. ³

Seforno: It was a test to see whether Yisrael would carry out Hashem's will, now that they were receiving their food and clothes ⁴ without effort on their part. ⁵

Seforno: Hashem knows what is in a person's heart, and the objective of the test was to actualize their thoughts into deeds, to let the angels know that Yisrael's level is truly superior to that of the angels. ¹

Rashi: With reference to the preceding phrase - "Le'ma'an Anoscha le'Nasoscha la'Da'as ... ", ¹ it is a prohibition against testing Hashem and querying His actions. ²