Midrash su Osea 7:4

And the people took their dough before it was leavened … upon their shoulders (Exod. 12:34). This indicates that the dough did not have sufficient time in which to leaven. Similarly, concerning the Messianic days, it states: Who ceaseth to stir from the kneading of the dough until it be leavened (Hos. 7:4). Their kneading troughs (mish’arotam), alludes to the leftover (shi-yu) unleavened bread and bitter herbs. You may interpret it so, but perhaps it does not refer to the remnants of the unleavened bread and bitter herbs, but to the remnants of the Passover sacrifices? However, since Scripture says of the paschal sacrifice: And ye shall let nothing of it remain until the morning (Exod. 12:10), it could not refer to the leftovers of the paschal sacrifices. Upon their shoulders (ibid., v. 34). Did they have no beasts of burden to carry the remnants of the unleavened bread and bitter herbs? After all, it is written: And a mixed multitude went up also with them; and flocks, and herds, even very much cattle (ibid., v. 38)? They did so because they cherished their religious obligations deeply. And so it is written: upon their shoulders.

(Ibid. 34) "And the people took their dough before it leavened": We are hereby apprised that they kneaded the dough, which had not risen to (become) chametz before they were redeemed. And thus (i.e., a similar metaphor) do you find in time to come, viz. (Hoshea 7:4) "they are all adulterers, like an oven fired by a baker, their arousing (the evil inclination) ceasing, (only) from the kneading of the dough until its leavening," (when they commit the act). And (Ibid. 5) "On the day of (the ascension of) our king, the princes took sick with wine, etc." (Exodus 12:34) "their remnants": of matzoh and maror. You say this, but perhaps (the reference is to) remnants of the Paschal lamb? (Ibid. 10) "And you shall not leave over anything of it (the Paschal lamb)" already accounts for the Paschal lamb. How, then, am I to understand "their remnants bound up in their clothes"? As referring to the remnants of matzoh and maror. ("their remnants) bound up in their clothes on their shoulders": R. Nathan says: Were there no beasts there (to carry the remnants)? Is it not written (Ibid. 38) "And also a great multitude went up with them, and flocks and herds"? Why, then, "on their shoulders"? To betoken their love of the mitzvoth.