Bava Metzia 44-50
"He (Hashem) Who punished the Generation of the Flood, the Generation of the Tower of Babel Dispersion, the people of S’dom and Amorah and the Egyptians in the Sea — He will also in the future punish a person who does not keep his word.”
This teaching in the mishna on our daf is discussed in greater detail in the gemara that follows (47b), detailing whether in Torah law a buyer acquires the item when he gives money for it, or if the buyer must take actual physical possession of the item (“meshicha”) in order to acquire it.
If a transaction was agreed upon verbally, and money changed hands for the purchase, but no act of the buyer taking physical possession occurred, the sale is not concluded according to halacha and either party may back out of the transaction. However, there are consequences and repercussions for the one who backs out and does not keep his word, as taught by the strong curse in the mishna.
Why is the person who fails to keep his word punished by Hashem in this manner, with a curse that mentions these specific historical Heavenly punishments? The Maharsha explains that “faithlessness” was the common denominator of all the wicked people mentioned in the mishna, whereas faithfulness is considered an inherent, basic Jewish trait.
I once heard from a great rabbi in Jerusalem that punishments mentioned in the mishna are not only of an epic nature, but also miraculous in nature. Likewise, a person who does not keep his word is guilty of failing to recognize the extraordinary power of human speech that Hashem breathed into Mankind, a power that can even bring miraculous and supernatural positive results when used in the correct manner.
Bava Metzia 44a