וַיִּשָּׂ֥א הָעָ֛ם אֶת־בְּצֵק֖וֹ טֶ֣רֶם יֶחְמָ֑ץ מִשְׁאֲרֹתָ֛ם צְרֻרֹ֥ת בְּשִׂמְלֹתָ֖ם עַל־שִׁכְמָֽם׃
Y llevó el pueblo su masa antes que se leudase, sus masas envueltas en sus sábanas sobre sus hombros.
Rashi on Exodus
טרם יחמץ BEFORE IT WAS LEAVENED — The Egyptians would not allow them to stay long enough for the dough to become leavened.
Rashbam on Exodus
בצקו, a construction from the root בצק, just as כתפו, “his shoulder,” is derived from the root כתף.
Tur HaArokh
משארותם צרורות בשמלותם על שכמם, “their leftovers bundled up in their garments, flung over their shoulders.”
Ibn Ezra understands the word משארותם as referring to wooden bowls used to knead dough in. The word appears in this context in Deuteronomy 28,17 טנאך ומשארתך, “your fruit basket and your kneading bowl.” They flung this over their shoulders as their donkeys were fully loaded with all the fancy garments they had taken from the Egyptians. I find this illogical, for would it not have been simpler for them to place the heavy wooden bowls on the donkeys and to carry the lighter garments on their shoulders?