Why the cost must be zero

The Torah says to send away the mother before taking the young, "so that it will be good for you, and you will prolong your days." Rashi explains: if the Torah promises this for an easy mitzvah with no financial loss, how much more for demanding mitzvos.

This explains why the Torah places its promise here. The easy mitzvah supplies the starting point for a kal vachomer, an inference from the lighter case to the heavier ones.

But if sending away the bird costs even a small coin, what establishes the reward for mitzvos that cost nothing? Saying Shema, for example, requires no purchase. A promise attached to a small expense would not, by this argument, cover a case with no expense. Rashi needs zero, not approximately zero.

Yet the mother bird has value. Calling Rashi's approach peshat, the plain reading, does not make her worthless. The Rebbe must explain how sending her away entails no loss.2

Why a missed gain still matters

Perhaps nothing leaves the person's pocket. The bird was never his; he merely passes up a possible gain.

The Rebbe rejects this answer. Even a child minds missing something he could have had. If the starting point must be a mitzvah without financial difficulty, renaming a loss "missed gain" has not removed the difficulty.

The Rebbe's answer relies on the mother's natural tendency to return to her young. The question becomes what her return permits.

In practical halacha, a returning mother must be sent away again while the original obligation continues, "even a hundred times." In the Rebbe's explanation of Rashi's peshat, however, the first sending fulfills the obligation. The original conditions of the encounter have changed; her return does not renew that same obligation, and the returning mother can be retained. On this reading, even the possible gain has not been forfeited.

The bird's value is the same; what differs is the obligation governing her return.3

Already at the nest

There is still a difficulty. Sending a bird away takes action. Saying Shema requires only speech. Why choose the nest as the easiest case?

The Rebbe asks when the obligation arises. In this peshat account, it arises when the person wants to take the young. He is already occupied with the nest for his own purposes. Someone busy elsewhere, with no intention of taking the young, is not being called away from his business.

Shema can require precisely such an interruption. Its words may be easy to pronounce while breaking off an absorbing occupation is difficult. At the nest, the person is already engaged in the activity that brings the obligation. Rashi's example therefore removes both financial loss and this competing demand on his attention.4

The next mitzvah costs money

The next verse says: "When you build a new house, you shall make a guardrail for your roof."

Rashi connects it to the nest. Fulfill that mitzvah, and you will come to build a new house and fulfill the mitzvah of a guardrail, because "one mitzvah leads to another." He then mentions a vineyard, a field and fine clothing, without expressly naming their mitzvos. Why name the guardrail?

In the Rebbe's peshat explanation, it resembles the first mitzvah. Both obligations arise while a person pursues something for himself: taking young birds or building a house. Both restrain cruelty within that activity. He must release the mother before taking the young; he must protect others from the danger of his roof.

The house thus brings two things: a material blessing and a particular continuation of the first mitzvah. Yet the second act asks more of him. A guardrail costs money. The resemblance makes it a fitting continuation; the expense means that continuing requires more than his first act did.5

An awakening with limited reach

The Rebbe's Chassidic explanation returns to the words shale'ach teshalach, "you shall surely send." The first word is an infinitive, called makor, "source," in Hebrew grammar. In his inward reading, an act commanded in this form should express the source of the person's faculties: the will and, more deeply, the essence of the soul.

Our ordinary faculties, including understanding and feeling, have limits. An act animated by them shares those limits. The soul's essence is not bounded in that way. When it finds expression through the faculty of action, it can carry that action beyond its ordinary limits. The Rebbe relates this to the halachic reading of "even a hundred times."

Yet in the peshat account the same word calls for one sending. The Rebbe relates this to the beginning of a person's service of Hashem. The source can awaken while its effect on the faculties through which he thinks, feels and acts remains limited. He explains that an awakening can come from Above without the person's preparation. It can reach the soul's source before it has become closely connected with those ordinary powers.

There is a real change: someone who previously gave no thought to mitzvos now performs one. Yet he may still be willing to do only what costs nothing, not even an issar. In the person the Rebbe describes, both are true: he has been moved to observe a mitzvah, and his readiness to sacrifice remains limited. The depth from which the awakening comes and the extent of its present effect are different measures.6

When the awakening becomes a deed

The Rebbe makes the next step depend on the awakening reaching an actual deed. The person fulfills the easy mitzvah, and "one mitzvah leads to another": sending away the mother draws him toward the guardrail, which does involve expense.

The first mitzvah allows the person to act while his readiness to sacrifice is still so narrow. The next resembles it, yet asks for an expense he was not initially ready to bear. Giving the awakening expression in the first deed can lead him that far. At the roof, he is prepared to spend so that someone else will not fall.6

Source notes

[1] The previously reconciled index contains two records: Toras Menachem 46, pp. 412-417, Bamidbar 5726, §ה and note 36; and Toras Menachem 50, pp. 338-349, Ki Seitzei 5727, §יג and note 90. The former uses the daf's phrase about a world that is wholly long; the latter examines the Mishnah's small-coin measure. Likkutei Sichos 9 is the fuller edited treatment of the second teaching, not a third indexed record. Both Toras Menachem records have missing-ending notices; vol. 50 also records an earlier lacuna and announces a separate discourse not reproduced there.

[2] Likkutei Sichos 9, Ki Seitzei I, printed pp. 133-134, §§א-ב; Chullin 142a, final Mishnah; Rashi on Deuteronomy 22:7.

[3] Likkutei Sichos 9, §§ג-ד and ז, pp. 134-137; Toras Menachem 50, §יג, pp. 347-348; Chullin 141a, repeated sending; Rashi on Deuteronomy 22:6. The article's natural-behavior qualification prevents the explanation from becoming an empirical guarantee.

[4] Likkutei Sichos 9, §§ה, ח-ט, pp. 135-138; Toras Menachem 50, §יג, pp. 348-349. This presents the peshat argument, not an independent ruling on the circumstances in which one must perform shiluach haken.

[5] Rashi on Deuteronomy 22:8; Likkutei Sichos 9, §§י-יא, pp. 138-140, including the peshat qualifications in the notes. The similarity explains this particular sequence; it is not presented as a universal restriction on "one mitzvah leads to another."

[6] Likkutei Sichos 9, §§יב-יג, pp. 140-141, especially note 39. The final sentence joins the source's explicit account of preventing cruelty in §י to its explicit expense-bearing continuation in §יג. No additional psychological mechanism is claimed.