Why do three angels go to see Avraham? Rashi suggests that one is to visit Avraham, the second is to tell Sarah that she is going to have a child, and the third is there to help Lot in Sedom. We must ask, though, why one angel could not do all these things by himself. After all, these three tasks did not occur at the same time; why couldn’t one angel do all three?
I would like to suggest that the number three symbolizes the continuation of the world. Pirkei Avot states that the world stands on three things: Torah – which can refer to the Mitzvot, Avoda – serving Hashem with prayer, and Gemilut Chassadim – good deeds. Avraham was doing all three things and thus kept the world going.
Even though Avraham was sick from his Brit Mila and was in a lot of pain, he still acted with Chessed towards the three angels. The Mitzva of Hachnasat Orchim was Avraham’s Chessed.
Before Avraham invited the angels into his house, he asked them to wash their feet. Rashi explains that Avraham wanted to wash off their gods, the dust of the earth, from their feet. By doing this Avraham showed that he fully believed in Hashem and did not allow Avoda Zara to enter his home. This is Avraham’s Avoda.
Third, Avraham sacrificed his own well being in order to fulfill the Mitzva of Brit Mila. Although he was old and Mila was dangerous, Avraham followed the word of Hashem and fulfilled the Mitzva. Avraham was committed to Hashem’s laws and he fulfilled them even when they included dangerous surgery at the age of 100. Furthermore, there is a Midrash that states that the Avot kept all the Mitzvot. Avraham held the world up with his observance of the Torah’s Mitzvot.
It therefore seems that the three angels came to point out to us that Avraham was holding up the world with the three aspects of Torah, Avoda, and Gemilat Chessed. Hopefully this Parsha can help us understand that the world will continue to function properly only if we, like Avraham, do our part in keeping it steady. The Mishna in Pirkei Avot tells us how: Torah, Avoda, and Chessed.