Refining Body Reveals Neshamah
בפסוק בנים אתם לה"א
Regarding the verse, "You are children to Hashem your God" (Devarim 14:1).
The Sfas Emes opens with the verse in which Hashem calls Bnei Yisrael His children, the foundation for the entire piece.
ופליגי בברייתא ר"מ אומר אם נוהגין מנהג בנים ור"י אומר ב"כ וב"כ קרוין בנים כדאיתא בקדושין ל"ו
There is a dispute in a braisa: Rabbi Meir says that we are called children only when we conduct ourselves in the manner of children, while Rabbi Yehudah says that whether one way or the other, we are still called children, as it is brought in Kiddushin (36).
He cites the Tannaitic dispute over whether the title "children" depends on our conduct (Rabbi Meir) or remains ours unconditionally (Rabbi Yehudah).
ויש להקשות האיך אפשר הבן להתחלף הלא זה החילוק בין בן לעבד כדאיתא בזוה"ק עבד אי לא יפלח כדחזי יעביר לי'
One must ask: how is it possible for a son to be exchanged for something else? After all, this is precisely the distinction between a son and a servant, as it is brought in the holy Zohar: regarding a servant, if he does not serve as is proper, his master will pass him off to another.
He raises a difficulty: the very difference between a son and a servant is that a son's status cannot be traded away, as the Zohar illustrates with a master who casts off an unworthy servant but never simply replaces a son.
אבל ברא או יקטלוני' או יעבד רעותי' ואיך יוכל להשתנות מעבד לבן
But a son, the master will either put him to death or compel him to do his will, yet how can a son be transformed into a servant?
He sharpens the question: a master may punish or coerce a wayward son, but a son cannot actually be downgraded into a servant, so how could the title "children" ever be forfeited?
אבל התירוץ הוא כמ"ש במ"א כי בוודאי בנים קאי על הנשמה ולא על הגוף שבא מט"ס
But the resolution is as I have explained elsewhere: certainly the term "children" refers to the neshamah and not to the body, which comes from the side of impurity.
He answers that "children" refers to the neshamah, the soul, not to the physical body, which originates from the realm of impurity.
וכפי זיכוך הגוף זוכין להארת הנשמה
And according to the degree to which the body is refined, one merits the illumination of the neshamah.
The illumination of the neshamah shines into a person in proportion to how much he refines and purifies his body.
ונק' בנים
And then one is called a child.
When that refinement is achieved, the person is truly called a child.
וז"ש אם אתה נוהג מנהג בנים שנמשך הגוף אחר כח הנשמה
And this is the meaning of "if you conduct yourself in the manner of children" — that the body is drawn after the power of the neshamah.
Conducting oneself "in the manner of children" means letting the body be led by the strength of the neshamah.
חל על הגוף גם הארת הנשמה
Then the illumination of the neshamah rests upon the body as well.
When the body submits to the neshamah, the neshamah's light comes to rest on the body itself.
ואם לאו מסתלק הארת הנשמה ח"ו
But if not, the illumination of the neshamah departs, Heaven forbid.
When the body does not submit, that illumination withdraws, a tragic loss, Heaven forbid.
ובשבת שהוא יומא דנשמתא נק' בנ"י בנים לעולם:
And on Shabbos, which is the day of the neshamah, Bnei Yisrael are called children forever.
On Shabbos, which is the day belonging to the neshamah, the body is fully aligned with the soul, so Bnei Yisrael bear the title of children permanently and without condition.
Summary: The Sfas Emes addresses the verse "You are children to Hashem," together with the dispute of whether Bnei Yisrael are called children only when they act accordingly or always. He asks how the title "children" could ever be lost, since the very distinction between a son and a servant is that a son's standing is permanent and cannot be exchanged. He resolves that "children" refers to the neshamah rather than to the body, which derives from the side of impurity; the light of the neshamah shines into a person according to how much he refines his body. When the body is drawn after the power of the neshamah, the soul's illumination rests upon it and one is truly called a child, but when the body resists, that illumination departs, Heaven forbid. On Shabbos, the day of the neshamah, the body and soul are perfectly united, so Bnei Yisrael are called children forever and unconditionally.