The Zohar asks about the verse, “The Lord Appeared to Him by the Oaks of Mamre,” why Mamre and not elsewhere? It is because he advised him about the circumcision.
When the Creator told Abraham to circumcise himself, he consulted his friends. Aner told him, “You are more than ninety years old and you will torment yourself.” Mamre told him, “Remember the day when the Chaldeans threw you in the furnace, and that famine that the world went through, etc., and they went down to Egypt, and those kings whom your men chased and whom you struck, and the Creator saved you from them all, and no one could harm you. Arise, do as your Master commands.”
The Creator said to Mamre, “You advised about the circumcision, be sure that I will be revealed only in your hall.” This is why it is written, “by the Oaks of Mamre.”
There is a famous question that when the Creator told Abraham to circumcise himself, he went and asked his friend. It seems as though he doubted whether he should heed the Creator.
We should also understand what this comes to teach us that the Creator said to him that He will be revealed to Abraham only in his hall. It would have been clearer had the Creator been revealed to Mamre himself than His revealing to Abraham only in the hall of Mamre.
According to the rule that the Torah is studied in a singular authority, it follows that his three friends, Aner, Eshkol, and Mamre were within him.
After he heard the Creator’s commandment, he went to his body so they would observe the Creator’s commandment. At that time, there were three views in his body: 1) Aner, which is 320 in Gematria, implying the 320 sparks in the body. In the 320, there is still the stony heart, which says, “I can do everything required of me, but I need to understand what I must do.”
The second one, Eshkol, comes from the word Eshkol [I will weigh/decide], meaning he weighs the matter. Once Aner said that he is a boy who does not understand what is required of him, Eshkol comes and weighs the benefits, meaning what the will to receive gains from this.
Sometimes, he also has the quality of Mamre, who counters the old man of Mamre, for “old man” is called “an old and foolish king.” Here Mamre speaks against Aner and Eshkol, arguing that he wants to go against reason, which is the quality of Aner, and against the will to receive, which is Eshkol.
This is the meaning of the advice he gave him about the circumcision, that specifically in the hall of Aner, meaning precisely in the place called “above reason.” Above reason because it is regarded as the Ruach of the will to receive, precisely in this place the Creator appeared to him, for precisely in this place there is the delight and pleasure. At that time, it is called “And you shall love the Lord your God with all your heart—with both your inclinations.”
It therefore follows that the three friends he went to ask refer to his own body, and they themselves must agree. If they do not agree then we must go by force. First, we must try in peace, but if it does not work in peace, then we must fight against the body.