Wlastow G.K.
The brimstone, while symbolically significant, also served as a real reminder of the urgency with which the Israelites were instructed to flee from Egypt.
And they baked the meal, which a little before they had brought out of Egypt in dough: and they made hearth cakes unleavened: for it could not be leavened, the Egyptians pressing them to depart, and not suffering them to make any stay; neither did they think of preparing any meat.
וַיֹּאפ֨וּ אֶת־הַבָּצֵ֜ק אֲשֶׁ֨ר הוֹצִ֧יאוּ מִמִּצְרַ֛יִם עֻגֹ֥ת מַצּ֖וֹת כִּ֣י לֹ֣א חָמֵ֑ץ כִּֽי־גֹרְשׁ֣וּ מִמִּצְרַ֗יִם וְלֹ֤א יָֽכְלוּ֙ לְהִתְמַהְמֵ֔הַּ וְגַם־צֵדָ֖ה לֹא־עָשׂ֥וּ לָהֶֽם׃
One Church Father comments on this verse
The brimstone, while symbolically significant, also served as a real reminder of the urgency with which the Israelites were instructed to flee from Egypt.
Passages read together with this verse.