The Alter Rebbe begins by clarifying that all of this applies specifically to someone who is לשומר התורה—careful to observe the Torah, and who ולא סר ממנה ימין ושמאל, אפילו כמלא נימא—has not deviated from it, not to the right nor to the left, even by the slightest amount, as thin as a hair.

In other words, the regular rules and limitations of mitzvos, including the mitzvah of tzedakah, are for someone who keeps the Torah exactly as it is supposed to be kept, without any deviation whatsoever. This person fulfills everything according to halacha, and so the measure and the amount that is required from him is defined and limited by the Torah itself.

However, the Alter Rebbe continues: what about someone שהעביר עליו הדרך ח"ו—who has strayed from the path, G‑d forbid? Since he has העוה דרכו—crooked his way, he has caused a deficiency לתת מגרעות בקדש העליון—he has brought a lacking into the supreme holiness.

That means he has diminished his own value, and more specifically, the level of divine energy he was supposed to draw down through his actions. The amount of G‑dliness and the radiance of the Infinite Light that he could have brought into the world, had he kept the Torah and observed it properly, is now missing. Because he did not fulfill the mitzvos as he should have, there is a real loss in the spiritual worlds—something is lacking in the קדש העליון, the supreme holiness above.

The Alter Rebbe explains that this kind of crookedness—where a person missed the opportunity to draw down a certain light through his mitzvos—is something that, on the surface, מעוות זה לא יוכל לתקן—cannot be fixed. Once the day has passed and the mitzvah was not done, the unique light that could have been drawn down is lost.

But there is a way to repair even this. The only way to fix it is בהמשכת האור העליון שלמעלה מהעולמות ואינו מתלבש בהן—by drawing down the supreme light that is higher than the worlds and does not become invested within them. This is what is called חסד עילאה—supreme chesed, and רב חסד—abundant kindness.

This is a different level of chesed than the regular chesed that is measured and limited. Here, the repair comes from a light that is completely above all limitations and boundaries.

Why is this supreme chesed able to fix what was lacking? Because מאיר ומתפשט בבחי' א"ס בלי גבול ומדה—it shines and spreads in a manner of infinity, without any measure or limit.

This light is not contracted within the worlds; rather, אלא בבחי' מקיף עליהן מלמעלה—it surrounds them from above. It extends from the very highest level, מריש כל דרגין עד סוף—from the beginning of all levels to the very end.

In other words, this is a light that is not confined by the structure of the worlds. It is a transcendent light, encompassing everything, and therefore it has the power to make up for what was missed, since it is not limited by the usual rules and boundaries.

When a person draws down this supreme light through his actions and through אתעדל"ת—isarusa d'letata, an arousal from below—then this higher light shines and spreads within the worlds.

This light is able to מתקן כל מעוות וכל מגרעות שניתנו בקדש העליון—fix all the crookedness and all the deficiencies that were caused in the supreme holiness. It doesn't just repair; it actually מחדש אורן וטובן, ביתר שאת ויתר עז, בבחי' אור חדש ממש—renews their light and their goodness, with even greater strength and power, like a completely new light.

So not only does Hashem restore what was missing, but He brings down an even greater light and goodness into the world, as a result of the person's effort to draw down this transcendent level. The repair is not just a patch; it is a renewal, a new infusion of divine energy that surpasses what was there before.

This is why our Sages say: במקום שבע"ת עומדין וכו'—in the place where a baal teshuvah stands, even a complete tzaddik cannot stand.

The reason is that the baal teshuvah, through his return and his efforts, draws down an even higher light than the tzaddik. The baal teshuvah brings into the world a level of בלי גבול—infinity, which is beyond all measure and limitation. This is the unique power of teshuvah: to reach and draw down the supreme chesed, the infinite light of the Ein Sof, and to bring about a renewal and elevation that even the greatest tzaddik cannot achieve through regular, measured service.