“And Hashem appeared to him in the orchards of Mamrei, and he was sitting at the opening of the tent in the heat of the day.” What does, “in the heat of the day” mean?
Rabbi Chama the son of Rabbi Chanina says: That day was the third day after Avraham’s bris milah. Hashem came to him to see how he was doing. Hashem therefore took out the sun from its sheath, so Avraham would not be disturbed with guests.
Avraham sent out Eliezer to go look for guests, but he came back empty handed. Avraham replied to him: I do not believe you (that there are no possible guests). This is the source of what is commonly said in Eretz Yisroel: There is no credibility in slaves. Avraham went out and saw Hashem by his doorway. This is why the verse says, “Please do not go away from Your servant.”
Tosfos writes that since Avraham asked Hashem to wait until he brings the guests inside, this would indicate that hosting guests is deemed to be even greater than greeting the Heavenly Presence.
The question is asked: How did Avraham Avinu know this halachah? Perhaps greeting the Heavenly Presence takes precedence over hosting guests? [There is an answer to this given in the name of the Noda Beyehudah.]
What is so unique about this mitzvah that it overrides a Shabbos prohibition (as the Gemora in Shabbos 127a derives) and is even greater then receiving the Divine Presence?
Rabbeinu Yonah writes that one honors his friend because his friend is a creation of Hashem. When one honors the prince, in effect, he is honoring the king. This is the deeper understanding of receiving and hosting guests. When a Jew receives Jewish guests and honors them as princes, in essence he is honoring the King, Hashem.
The Maharal writes that one cannot really honor Hashem as one cannot see Hashem and live. By receiving and hosting guests, one draws closer to the Divine Presence.
The brother of the Maharal writes in Sefer HaChaim that by performing the mitzvah of receiving and hosting guests, one will be quicker to improve on his service of Hashem. A person will say to himself, “If I can do so much for my friend who is my guest, certainly I can perform the mitzvos in a more wholesome fashion.”