Parshas Korach: Chasam Sofer – Dasan or Aviram’s Debt of Gratitude To Moshe
“Vlo Harai’osi Es Achad Mayhem”, neither have I wronged one of them (Korach 16:15). The words Es Achad Mayhem, “one of them” seems extra. He could have simply said , “Vlo Hariosi Lahem” – “I did not wrong them”?
The Chasam Sofer answers, when Moshe visited his brothers in the fields of Mitzrayim, he noticed 2 Jews, Dasan and Aviram , fighting amongst themselves. When one lifted a hand against the other, he exclaimed, “Rasha, why do you strike your brother?” Moshe broke up the fight this sparing the other a beating.
When Korach came to argue with Moshe, he was joined by the infamous rebels, Dasan and Aviram. Moshe was shocked to see them and said in amazement, “the one I stopped from beating up his friend may have reason to be angry with me , but “Vlo Hariosi Es Achad Mayhem” – to one of them I did no evil – in fact I rescued him – why does he join my enemies?
from revach.net