When the Creator told Abraham to circumcise himself, he went to seek advice from his friends.

How can it be that he went to seek the advice of the friends if it was worthwhile to obey the Creator?

When the Creator told him to circumcise himself, he went to consult his friends, meaning his body, since the body is the one who must execute the action. That is why he asked his body if it agreed or if its view is that he needn't obey the Creator's command. Man's friends, - the desires of the body, which he must ask because they must carry out this commandment of the Creator. And when he knows their view, he will know what to do.

There are three souls in the body, as it is written in The Zohar (VaYera, Item 315). The governance of mind and wisdom - the power of the holy soul. The governance of lust that craves after ill will, - that is the power of lust. The governance that guides people and reinforces the body - the Nefesh (soul) of the body.

They are called "friends," for he includes them. And Abraham wanted to know their views.

Aner said: You are old, so do not inflict pain upon yourself. Aner in Gematria is 320, implying the 320 sparks that include Malchut of the stony heart, the will to receive in order to receive, self-love. The stony heart, the craving soul always tries to receive delight and pleasure. Thus, he told him that it was not worthwhile to obey the Creator's command.

Mamre said: The Creator saved you from the furnace, the Creator treats you above reason, because according to reason you would have burned. Hence, you too, cleave to His attributes and go above reason, although reason justifies Aner. Since Mamre advised having the circumcision, "And the Lord appeared to him by the oaks of Mamre." 

Eshcol - the Nefesh (soul) of the body that strengthens the body, weighs with whom it is better to bond, with the lusting soul, "Aner," or with Mamre, who is the soul of reasoning and wisdom. That is the power of the holy soul.

Mamre is against Aner and told him to go above reason. That is "And the Lord appeared to him by the oaks of Mamre," where one goes above reason, without intellect, that is where the Creator appears and knowing Kedusha (holiness) is revealed. It is called "Mamre," above reason, the soul of reasoning and wisdom, since in a place where one goes above reason, reasoning and wisdom are revealed.

Abraham went to seek the advice of "his friends," with his own body, which must carry out the Mitzva (commandment), hence he asked for the body's view so he would know what to do. Whether he should coerce himself or rather they agree with the Creator. His  friends are the three souls of the body.

It is written [in Midrash Raba (end of the portion Lech Lecha (Go Forth) and beginning of VaYera (And the Lord Appeared),] "Abraham said, ‘Before I was circumcised, passers by would come to me. Since I was circumcised, they do not come to me.' The Creator said to him, ‘Before you were circumcised, uncircumcised people would come; now I and My company appear unto you.'"

Before he was circumcised, he had thoughts of passers by (also transgressors), and afterwards he had the returning (also repenting), for he knew that he was a worker. Now there were no passers by, yet he longed for work.

Hence, the Creator told him, "You should not regret not having the work of uncircumcised people. Now that you have been circumcised, there is equivalence of form and I may appear unto you."