"And they baked the dough" (Exodus 12:39). This tells that they kneaded the dough but did not manage to leaven it before they were redeemed. And likewise you find for the time to come, what does it say (Hosea 7:4), "He shall cease from the city, from the kneading of the dough until it is leavened." "Cakes of unleavened bread": "cakes" means nothing other than a flat baked cake, as it is said (Ezekiel 4:12), "And you shall eat it as barley cakes," and it says (1 Kings 17:13), "Make me from it a small cake." A great miracle was performed for them with that cake, for they ate from it for thirty days until the manna came down for them. "Because they were driven out of Egypt" (Exodus 12:39). I might understand of their own accord; Scripture teaches, "And could not tarry," until they were redeemed. "Neither had they prepared for themselves any provision" (Exodus 12:39). This proclaims the praise of Israel, that they did not say to Moses, "How can we go out into the wilderness when we have no sustenance for the way?" Rather, they believed and went after Moses. Concerning them it is explained in the tradition (Jeremiah 2:2), "Go and proclaim in the ears of Jerusalem" and so forth. What reward did they take for this? (Jeremiah 2:3) "Israel is holy to the LORD" and so forth.
Unleavened Cakes Baked in Haste and Israel's Trusting Faith
Yalkut Shimoni on Torah 209:2
(שמות יב לט) וַיֹאפוּ אֶת הַבָּצֵק. מַגִּיד שֶׁלָּשׁוּ אֶת הָעִסָּה וְלֹא הִסְפִּיקוּ לְחַמְּצָהּ עַד שֶׁנִּגְאֲלוּ. וְכֵן אַתָּה מוֹצֵא לֶעָתִיד לָבֹא מַהוּ אוֹמֵר (הושע ז, ד) "יִשְׁבּוֹת מֵעִיר מִלּוּשׁ בָּצֵק עַד חֻמְצָתוֹ". עֻגֹת מַצּוֹת, אֵין עֻגֹת אֶלָּא חֲרָרָה שֶׁנֶּאֱמַר (יחזקאל ד, יב) "וְעֻגַת שְׂעֹרִים תֹּאכְלֶנָּה" וְאוֹמֵר (מלכים א יז, יג) "עֲשִׂי לִי מִשָּׁם עֻגָה קְטַנָּה". נֵס גָּדוֹל נַעֲשָׂה לָהֶם בַּחֲרָרָה שֶׁהָיוּ אוֹכְלִין מִמֶּנָּהּ שְׁלֹשִׁים יוֹם עַד שֶׁיָּרַד לָהֶם הַמָּן. כִּי גֹרְשׁוּ מִמִּצְרַיִם. שׁוֹמֵעַ אֲנִי מֵאֲלֵיהֶם תַּלְמוּד לוֹמַר וְלֹא יָכְלוּ לְהִתְמַהְמֵהַּ עַד שֶׁנִּגְאֲלוּ. וְגַם צֵדָה לֹא עָשׂוּ לָהֶם. לְהוֹדִיעַ שִׁבְחָן שֶׁל יִשְׂרָאֵל שֶׁלֹּא אָמְרוּ לְמֹשֶׁה הֵיאַךְ אָנוּ יוֹצְאִין לַמִּדְבָּר וְאֵין בְּיָדֵינוּ מִחְיָה לַדֶּרֶךְ, אֶלָּא הֶאֱמִינוּ וְהָלְכוּ אַחֲרֵי מֹשֶׁה. עֲלֵיהֶם מְפֹרָשׁ בַּקַּבָּלָה "הָלֹךְ וְקָרָאתָ בְאָזְנֵי יְרוּשָׁלַיִם" וְגוֹ'. מַה שָׂכָר נָטְלוּ עַל כָּךְ, (שם ג) "קֹדֶשׁ יִשְׂרָאֵל לַה'" וְגוֹ'.