According to R. Akiva and R. Gamliel B'no Shel R. Yehudah ha'Nasi, ¹ Hashem's reply is self-evident - inasmuch as the quails that blew in from the sea for thirty consecutive days provided for the people just as He said they would, and inasmuch as they satisfied their desire for meat.

Rashi (on Pasuk 22, according to R. Shimon): Seeing as, if He would not give them what they asked for, they would accuse Him of being incapable of granting their request, it is preferable that they should perish - and a hundred like them, than that they consider Hashem's Hand short, even for one moment.

Ramban (on Pasuk 22): Refer to 11:22:1:4*. He informed Moshe that He was perfectly capable of satisfying Yisrael' desires by natural means, without performing a miracle. ²

Rashi: When, responding to Moshe's question, Hashem said 'Im-Ken Yomru ha'Yad Hashem Tiktzar', Moshe volunteered to go and appease the people, Hashem informed him that he would see how his efforts would be in vain since they would merely accuse him of compromising ¹ and that consequently, what He (Hashem) had told Moshe would prevail.

Ramban: ?I will carry out what I said in a perfectly natural way, without a miracle?. ²

Seforno ³ : Hashem was informing him that He was perfectly capable of satisfying the people to the point that what he gives them will disgust them - that of their own freewill they will be drawn after the meat that He sends them, until they are sick of it and 'it comes out of their nostrils', just as He predicted. ⁴

Da'as Zekenim #1: 'Just like I can hold in My hand, I can hold in their hands, until My word is fulfilled?. "u'che'Amasayim al-Pnei ha'Aretz" ' ? they did not even need to move their hands.

Da'as Zekenim #2: 'You were concerned because animals must be offered as a Korban ? I will give them fowl, which are not subject to Korbanos'.