The Pupa Rav, Rav Yosef Greenwald, was a devoted Belzer Chossid. After the war he settled in Williamsburg and established the contemporary Pupa Chassidus. He travelled to Belz many times before the war, and after the war he made the trip from America to Eretz Yisroel to come to the Ruv Z”L, Reb Aharon.
One of the times that he went in to the Ruv Z”L it was on Parshas Vayeira. The Ruv Z”L asked him the following question. Three Malachim visited Avraham Avinu. Rashi explains why were there three Malachim. One to heal Avraham Avinu, one to bode the good news to Sarah Imeinu, and one to overturn Sedom.
The Ruv Z”L asked the Pupa Rav, why did the Malach that was supposed to overturn Sedom visit Avraham Avinu?
The Pupa Rav responded that since there are three parts to the Mitzvah of Milah, חיתוך, פריעה, ומציצה, and for every Mitzvah a Malach is created, these three Malachim were the Malachim created by the Mitzvah Avraham Avinu did.
The Ruv Z”L was very satisfied with the answer. Throughout that day, whoever came to the Ruv Z”L, he asked, “Did you hear what Pupa Rav said?” and repeated the answer.
The Pupa Rav later recalled that he was taken aback since it wasn’t customary of the Ruv Z”L to ask questions, but he davened to Hashem to have the right answer, and B”H the Ruv Z”L accepted the answer.