Targum Pseudo-Jonathan on Exodus 16:20 names names. The Hebrew only tells us that "some of them" kept manna overnight against Moses's word. The Targum identifies the culprits: But some of them hearkened not to Mosheh: Dathan and Abiram, men of wickedness, did reserve of it till the morning; but it produced worms and putrefied; and Mosheh was angry with them.
Dathan and Abiram. The Sages recognized them. These are the same two troublemakers who will later side with Korah in his rebellion (Numbers 16) and be swallowed alive by the earth along with their tents. Here, in Exodus 16, they are making their first cameo as anshei rish'a, men of wickedness. The Targumist is drawing a narrative arc.
What did they do wrong? They did not trust the daily dispensation. Moses had said: gather the matter of a day by the day. Dathan and Abiram thought they knew better. They stockpiled. The next morning, their private stash had bred worms and stank. The Sages read this as a physical judgment that fit the sin exactly. The manna they hoarded mimicked, in miniature, what hoarding does to a soul: it rots.
The <a href='/categories/midrash-aggadah.html'>aggadic tradition</a> amplifies the detail. The daily gift of manna was not just food. It was a pedagogy of trust. Those who could not practice it in the small matter of breakfast would, predictably, also fail in the large matter of loyalty to Moses's leadership. The worms in the pot foreshadowed the earth that would open under their feet.
The Maggid's takeaway is blunt. The sin of hoarding is not that it offends an arbitrary rule. It is that it betrays a lack of faith in tomorrow's portion. If you cannot trust the Holy One to send tomorrow's manna, you will also find yourself unable to trust Him in any larger test. Small distrust breeds worms. Large distrust opens the ground.