Mitzvos as Unified Whole
במדרש תנחומא מכל משמר כו' כי ממנו תצאות חיים
In the Midrash Tanchuma it states: 'Above all that you guard, watch your heart, for from it are the sources of life' (Mishlei 4:23).
The Sfas Emes opens with a Midrash citing the verse that, above everything a person guards, he must guard his heart, because from it flow the sources of life.
דהל"ל מהם
It should have said 'from them' (in the plural, referring to the things one guards).
He raises a grammatical difficulty: since 'all that you guard' is plural, the verse should logically have continued 'from them' rather than 'from it.'
רק דקאי על הכלל מכל משמר כי לעיקר החיים זוכין בצירוף כל המצות שניתקן כל האדם ע"י תרי"ג מצות כמ"ש במד' חיים הם למוצאיהם שממצה אותם כדכ' כל המצוה ע"ש פ' עקב
Rather, the verse refers to the totality: 'Above all that you guard' — for the essence of true life is attained only through the combination of all the mitzvos, since the entire person is set right and made whole by means of the six hundred thirteen mitzvos. This is as the Midrash says, 'They are life to those who find them' (Mishlei 4:22) — to one who fully extracts and exhausts their meaning, as it is written, 'all the mitzvah' (Devarim 8:1), see there in Parshas Eikev.
He answers that the singular 'from it' points to the unified whole of all the mitzvos taken together. A person becomes a complete being only through the full set of six hundred thirteen mitzvos, and true life flows from one who fully extracts the depth of the mitzvos.
וזה משל הפרדס שמביא המד' כי בפרט יש קלות וחמורות אבל עיקר השכר כשזוכין לשלימות הפרדס כי כרם ה' בית ישראל
And this is the meaning of the parable of the orchard that the Midrash brings: for among the individual mitzvos there are lighter ones and weightier ones, yet the essential reward comes when one merits the completeness of the whole orchard, for 'the vineyard of Hashem is the House of Yisrael' (Yeshayahu 5:7).
This is why the Midrash brings the parable of an orchard: individual mitzvos vary in weight, but the real reward is for attaining the wholeness of the entire 'orchard,' since Bnei Yisrael as a collective are Hashem's vineyard.
ובזה קלה כחמורה
And in this respect a light mitzvah is like a weighty one.
When viewed as part of the complete whole, even a seemingly minor mitzvah carries the same value as a major one.
ובמד' לוית חן הם כו'
And in the Midrash it expounds the verse 'they shall be a graceful wreath' (Mishlei 1:9), etc.
He now turns to another teaching of the Midrash on the verse describing mitzvos as a graceful wreath and chains.
כי המצות בעשי'
For the mitzvos are performed through action.
The basic nature of mitzvos is that they are carried out through physical action.
ומ"מ על ידיהם זוכין גם לבחי' מחשבה ודיבור
Yet nonetheless, by means of these deeds one merits also to the levels of thought and speech.
Even so, performing these physical deeds elevates a person to the higher dimensions of thought and speech as well.
חן לראשך הוא הנשמה בחי' מחשבה
'A graceful wreath for your head' — this is the neshamah, the aspect of thought.
The 'graceful wreath for your head' alludes to the neshamah, which corresponds to the dimension of thought.
וענקים לגרגרותך הדיבור שכשניתקן הגוף ונפש ע"י המעשים ממילא זוכין אח"כ לרוח ולנשמה כנ"ל:
'And chains for your throat' — this is speech; for once the body and the nefesh are set right through the actions, one then automatically merits afterward to the levels of ruach and neshamah, as explained above.
The 'chains for your throat' allude to speech; once a person refines his body and nefesh through physical mitzvos, he automatically rises afterward to the higher levels of ruach and neshamah.
Summary: The Sfas Emes examines a Midrash on the verse 'guard your heart, for from it are the sources of life,' asking why it says 'from it' in the singular when one guards many things. He answers that the singular points to the unified totality of all the mitzvos: a person becomes complete and attains true life only through the full set of six hundred thirteen mitzvos taken as one whole, which is why the Midrash compares Bnei Yisrael to a single orchard or vineyard of Hashem. Within this complete whole, a light mitzvah carries the same weight as a heavy one. He then explains that although mitzvos are fundamentally performed through physical action, refining the body and nefesh through deeds automatically draws a person upward to the higher dimensions of speech and thought, the levels of ruach and neshamah hinted at in the 'graceful wreath' and 'chains.'