Milah Revealing Inner Light
במדרש בנולד כשהוא מהול צריכין להטיף ממנו דם ברית מפני בריתו של א"א ע"ה המל ימול כו'
The Midrash teaches that when a child is born already circumcised, one must still draw a drop of bris-blood from him, on account of the covenant of Avraham Avinu, peace be upon him, as the verse states, "He must surely be circumcised" (Bereishis 17:13).
Even a baby born without a foreskin needs a symbolic drop of blood drawn, because the bris of Avraham Avinu must be actively fulfilled and not merely happen on its own.
כי עיקר ברית מילה שניתן לא"א שיהי' בכחו וכח תולדותיו להסיר הערלה ולגלות אור הפנימי
For the essence of the covenant of milah that was given to Avraham Avinu is that it should lie within his power and the power of his descendants to remove the orlah (the foreskin) and thereby reveal the inner light.
The real point of milah given to Avraham is the God-given power, passed to his descendants, to strip away the orlah and uncover the inner spiritual light hidden within.
והנה המילה ניתן רק לבנ"י שהם בעצם נמולים כי נפשות בנ"י אין להם חלק בסט"א חלק ה' עמו ולכן גם בגשמיות הגוף צריכין להסיר הערלה זה המל ימול מי שהוא בעצם נימול ימול גם הגוף
Now, this covenant of milah was given only to Bnei Yisrael, who are circumcised in their very essence, for the souls of Bnei Yisrael have no portion in the sitra achra (the side of impurity), as the verse says, "Hashem's portion is His people" (Devarim 32:9); therefore in the physicality of the body as well they must remove the orlah. This is the meaning of "He must surely be circumcised" (Bereishis 17:13): one who is in his very essence already circumcised must circumcise the body as well.
Because the souls of Bnei Yisrael are intrinsically pure and already 'circumcised' at their root, the physical body too must have its orlah removed so that the outer form matches the inner reality.
וזה עיקר האות ברית שהוא עדות על שורש הנפש למעלה שאין בה ערלה וזה שורש כל המצות שברית מילה יצא מן הכלל ללמד על הכלל כולו יצא שכל האברים יש להם שורש למעלה וע"י רמ"ח ושס"ה מצות מדבקין הכלים שלמטה להיות דבקים בשורש כמ"ש במדרש לוית חן הם הוא התדבקות בשורשם
This is the essence of the os bris (the sign of the covenant), for it bears witness to the root of the neshamah above, in which there is no orlah; and this is the root of all the mitzvos, for the covenant of milah was singled out from the general rule to teach about the rule in its entirety, that just as it was singled out, so too all the limbs have a root above, and through the two hundred and forty-eight positive mitzvos and the three hundred and sixty-five prohibitions one binds the vessels below to be attached to their root, as the Midrash expounds on "They are a graceful garland (livyas chein) for your head" (Mishlei 1:9), that this refers to the cleaving of the limbs to their root.
The sign of the bris testifies that the neshamah's source above is free of any covering; milah is the model for all mitzvos, teaching that every limb has a spiritual root, and the six hundred thirteen mitzvos attach our physical 'vessels' to those roots.
ואז נק' תמים ושלם ואז חל עליהם הברכה
It is then that a person is called tamim (perfect) and shaleim (whole), and it is then that the berachah rests upon him.
Once a person achieves this attachment of all his limbs to their root, he is whole and complete, and only then can berachah settle upon him.
וזה ענקים לגרגרותך שאין כלי מחזיק ברכה אלא שלום כמו השבת שנק' שלום לפי שבו יש עלי' לתחתונים למעלה ולכן ויברך את יום השביעי כמו כן מילה בנפש כי שם צוה ה' את הברכה וא"א ע"ה הראשון וכ' והי' ברכה וה' ברך א"א בכל
This is the meaning of "and chains (anakim) for your throat" (Mishlei 1:9), for no vessel holds berachah except shalom, like the Shabbos, which is called shalom because through it there is an ascent for the lower realms to rise above; therefore the verse states, "And He blessed the seventh day" (Bereishis 2:3). So too the milah in the neshamah, for "there Hashem commanded the berachah" (Tehillim 133:3), and Avraham Avinu, peace be upon him, was the first, as it is written, "and you shall be a berachah" (Bereishis 12:2), and "Hashem blessed Avraham with everything" (Bereishis 24:1).
Berachah needs a vessel of shalom to hold it, just as Shabbos is called shalom and was blessed because it lifts the lower world upward; milah works the same way in the soul, and Avraham, the first to be blessed 'with everything,' embodies this.
ועוד לוית חן בנפש במעשה המצות
And further, "a graceful garland (livyas chein)" refers to the neshamah through the performance of the mitzvos with action.
The 'graceful garland' corresponds to the neshamah, which is refined specifically through the physical performance of mitzvos.
וענקים לגרגרותך בחי' רוח בקול ודיבור שזוכין אחר תיקון המעשה:
And "chains for your throat (gargerosecha)" alludes to the aspect of ruach, in voice and speech, which one merits after the rectification of action.
The 'chains for the throat' correspond to the level of ruach, expressed through voice and speech, which a person attains only after he has first perfected his actions.
Summary: The Sfas Emes explains that the covenant of milah given to Avraham Avinu is the power to remove the orlah and reveal the inner light, and that even a child born already circumcised needs a drop of bris-blood because the covenant must be actively fulfilled. Since the souls of Bnei Yisrael are intrinsically pure and have no portion in the sitra achra, the body too must shed its orlah so that the outer form reflects the inner reality, and milah thereby becomes the model for all mitzvos: every limb has a root above, and the six hundred thirteen mitzvos bind our physical vessels to those roots. Only when a person is thus attached to his root is he tamim and shaleim, a fit vessel for berachah, for berachah is held only in shalom, just as Shabbos is called shalom and was blessed. The Sfas Emes reads the verse in Mishlei on two levels: the 'graceful garland' is the neshamah refined through the performance of mitzvos in action, while the 'chains for the throat' are the level of ruach in voice and speech, which one merits only after first rectifying his deeds.