A. The purpose of the Mitzvah of Milah:[1]

The level of Avram: The name “Avram” stands for the words “Av/father” and “Ram/high”. This represents a level of intellect that is so elevated that it surpasses the conscious mind. This level of intellect is called “Sechel Hanelam Mekol Raayon/Intellect that is above all thought”. It is the level of Mochin [intellect] that surpasses even the level of Chochmah of Atzilus. [It is similar to a great and sublime idea that one has in the back of his mind but is unable to express in a way that others can understand. In G-dliness, this level represents the level of Mochin that is above Chochmah of Atzilus. This is known as Chochmah Setima.] Although this level of intellect is above comprehension, its purpose has to be revealed below; the objective is for this level of Mochin, which surpasses even Atzilus, to be drawn down to the lower worlds of Beriyah, Yetzira, and Assiyah. Accordingly, this is the meaning of the verse, “And Hashem said to Avram, ‘Go from your land’”: Hashem is telling Avraham that his sublime level of Av Ram should descend and reveal itself in order to refine and fix the world. Until the time of Avraham, the world had experienced “Sheviras Hakeilim”, the generation of the Flood. From Avraham began the world of Tikkun, which requires him to go out and begin to refine the world. Avraham embodied this very high level of G-dliness called Av-Ram, through the revelation of which he could perfect the world and make it a dwelling place for G-d.

The purpose of the Mitzvah of Milah: As a prerequisite for the revelation of the level of Av Ram, Avram had to perform the Mitzvah of Milah. The Arla [foreskin] represents the level of Kelipas Nogah [neutral evil] that covers over holiness and conceals it. So long as the foreskin surrounds holiness, the level of holiness cannot be revealed, as this would allow the side of Kelipas Nogah to nurture from this revelation and receive greater vitality and life-force then it was allocated during its creation. For this reason, after the Milah the verse states that that Avraham would be “Av Hamon Goyim/Father of all nations”, as the removal of Avraham’s Arla gave the ability for his level of Av Ram to be revealed and hence become a light onto the nations and assist them in their refinement. The refinement of the nation’s takes place due to a great revelation of G-dliness. This is similar to a great torch that attracts all of the smaller sparks to join it. Every item of food and drink contains Holy sparks within it. The torch of G-dliness uncovered through Avraham’s revelation would attract the sparks of G-dliness hidden throughout the nations of the world. The purpose of the Jews entering into exile is to refine these sparks and have them included within holiness. It is precisely the Mitzvah of Milah that allows the source of Holiness to be revealed and allows the sparks to become attracted to Kedusha.   

[1] Torah Or p. 11a