Exodus 12:39

עגת מצות means a cake of (made of) unleavened dough (Mekhilta); dough which has not become leavened is termed מצה. וגם צדה לא עשו להם NEITHER HAD THEY MADE FOR THEMSELVES ANY PROVISION for the journey. This is stated to tell how praiseworthy Israel was: that they did not say, “How can we go forth into the wilderness without provisions?” But they had faith and set forth. This it is that is referred to more explicitly in the prophets: (Jeremiah 2:1) “I remember for thee the affection of thy youth, the love of thine espousals, how thou wentest after me in the wilderness in a land that was not sown”. What reward is afterwards set forth there? “Israel is the Lord’s hallowed portion etc.” (Mekhilta).

וַיֹּאפ֨וּ אֶת־הַבָּצֵ֜ק אֲשֶׁ֨ר הוֹצִ֧יאוּ מִמִּצְרַ֛יִם עֻגֹ֥ת מַצּ֖וֹת כִּ֣י לֹ֣א חָמֵ֑ץ כִּֽי־גֹרְשׁ֣וּ מִמִּצְרַ֗יִם וְלֹ֤א יָֽכְלוּ֙ לְהִתְמַהְמֵ֔הַּ וְגַם־צֵדָ֖ה לֹא־עָשׂ֥וּ לָהֶֽם׃

And they baked unleavened cakes of the dough which they brought out of Miżrayim, for it was not leavened; because they were driven out of Miżrayim, and could not delay, neither had they prepared for themselves any provision.