The Revelation
 It was a very hot day since Hashem took the sun out of its sheath to avoid troubling Avrahom with his constant campaign of servicing guests by keeping all travelers indoors due to the intense heat. Avrahom was sitting at the entrance of his tent, gazing for passerby who could be invited to his home, which was located in the plains of Mamre, who merited Hashem's revelation on his property because he advised Avrahom to proceed with the bris. When Hashem came to him, Avraham wanted to stand up but Hashem told him to remain sitting as He stood. This was a harbinger for the future where Hashem stands in Beis Din as Avrahom's descendants, the judges sit.
 Entrance of the Tent
Avrahom reached the level of Hashem openly appearing to him by first entering the Chambers of Exchange and separating the good from the bad and extracting the holiness from there. Just like all those who wish to enter the Side of Holiness, Avrahom had to remain for a great many days at the entrance of the tent of Holiness, during which he was bombarded with intense opposition from the Other Side, and burning Yetzer Hara which got stronger as he neared the entrance. Such opposition caused many others to retreat; either because they did not realize they were right near the entrance or because the opposition was too intense. Avrahom patiently waited at the entrance, with great determination and did not retreat. This great opposition from the Other Side just caused him to be more vigorous in his efforts to come close to Hashem and circumcise his heart.
 The 3 Guests
When Hashem saw how troubled Avraham was that no guests were coming, He brought him angels appearing as men. Avrahom lifted his eyes and saw three men standing before him. He observed that they were standing in one place, and understood that they did not wish to burden him. Although they knew Avrahom would come out toward them, they stood in their place out of respect, to show him that they did not wish to trouble him when they saw him untying and tying his bandages,and started moving away. Avrahom went out first from the entrance of the tent and immediately ran toward them, with great speed and happiness in doing a mitzva, the ultimate true eternal goal. Avraham first asked Hashem to wait for him until he brought in the guests, also requesting that this great revelation should not completely leave him and residue should remain. that he can constantly use to energize himself with.
Avrahom prostrated himself to the ground and greeted them as lords and then turning to the main angel, requested if he found favor in his eyes, he should not pass away from him without being hosted. If the main angel would agree to remain, his companions would remain with him.
Since a single angel can not run more then one unrelated errand, three separate angels were sent. One to bring the news of Yitzchak's birth to Sarah, one to overturn Sodom, and Refoel to heal Avrahom and to save Lot.
 The Meal
Avraham asked that a little water should be brought. By doing this he was manifesting the bringing down of energy from his great spiritual revelation of Hashem appearing to him.
- ^ a b c d e f g h i j Rashi Berashis 18:1
- ^ a b c d e f g h i Likutay Halachos, Hilchos Ishus 4:19
- ^ Alim Letrufa, Letter 28
- ^ Likutay Moharan II 48
- ^ a b c d e f g h i j k Rashi Berashis 18:2
- ^ a b c d Rashi Berashis 18:3