כי תהיין לאישׁ שתי נשים וכו’ לא יוכל לבכר את בן האהובה על פני בן השְנואה הבכר

If a man has two wives, one beloved, and another hated . . . that he may not make the son of the beloved firstborn before the son of the hated, who is indeed the firstborn 

Deuteronomy 21:15-16

It is puzzling that the Torah felt it necessary to inform us of this law. For on what ground would we have supposed that a father, out of his love for the mother of the second son, could treat the second son as if he were his first-born son?

Our master explained that the Scripture is here warning us not to use the underlying rationale for a law as the basis for a halakhic inference (שלא נדרוש טעמא דקרא). Thus, one might have said that the reason why the Torah gave the first-born son the right to take a double portion of his father’s inheritance is that the first son issues from the union between a husband and the wife of his youth, motivated by a surpassing love and an absolute unity. As the product of such a loving union and the first fruit of his father’s strength, a first-born son is thus endowed with noble and honorable qualities, as the Sages teach (Nedarim 20b) is evident from the opposite situation: the children of enmity and of conflict become rebellious and sinful (Isaiah 1:4) “זרע מרעים בנים משחיתים” (offspring of evil-doers, sons who deal corruptly). And concerning the verse (Ezekiel 20:38) “וברותי מכם המרדים והפושעים בי” (I will remove from you those who rebel and transgress against Me) R. Levi teaches that the verse refers to the offspring of parents belonging to one of the nine categories of enmity between a husband and wife.

It might therefore be supposed that if a man has two wives — one beloved and one hated — and his first-born son is the child of the hated wife, the above reason for bestowing a double portion on the first-born son is invalid, so that the son of the beloved wife is the more deserving of the double portion. To counter such reasoning, the Scripture is teaching us here not to use the underlying rationale for the law as the ground for inferring any qualification in its application, and, thus, to allow the father to treat the son of the beloved wife as if he were the first-born son. The Torah emphasizes that it is the first-born son who is the first fruit of his father’s strength and therefore retains the right to be treated as the first-born son under all circumstances. (שביבי אש)

כי יהיה לאישׁ בן סורר ומורה איננו שמע בקול אביו ובקול אמו ויסרו אתו ולא ישמע אליהם

If a man has a stubborn and rebellious son, who will not obey the voice of his father, or the voice of his mother, and who, when they have chastened him, will not listen to them 

Deuteronomy 21:18

In the Sifri, R. Yehudah says that if the boy’s mother was unworthy of his father, he cannot be judged a rebellious son. The Sages say in the Talmud that he meant to say that the mother must resemble the father in voice, appearance and height. What does this mean?

Our master explained the matter in an aggadic fashion. In the normal course of events, a child will always listen intently to the words of his father and mother and will be very careful to obey and follow whatever they say. However, if the father and the mother are not in accord, but in conflict, with each other, so that his father guides him in one direction and his mother in another, then their honor will be diminished in his eyes. He will then no longer pay heed to either of them, even on a matter about which they agree. He will stop caring about what they say and will pay no attention to their advice, as we also know from experience.

This is what is meant by the verse a “כי יהיה לאיש בן סורר ומורה” (if a man has a stubborn and rebellious son). The reason that the son is rebellious is “איננו שמע” (he does not obey). But it is necessary to understand that the reason that the son does not give heed is that he cannot give heed to and obey “בקול אביו ובקול אמו”  (the voice of his father and the voice of his mother), the word “קול”  (voice) being repeated to signify that the parents’ opinions and advice is contradictory, so that the son cannot do the will of both. Thus, even if “ויסרו אתו” (they both chastise him) about a matter that they agree upon, “ולא ישמע אליהם” (he will give no heed to them), instead casting their words aside. It is about this situation that R. Yehudah said, if his mother was unworthy of his father, he cannot be judged a rebellious son, because such a verdict can be rendered only if the father and the mother are in accord in all their opinions and guide him along a single path. Only in this condition, may the verdict appropriate to a rebellious son be rendered upon him for not listening to them.

כי יקרא קן צפור לפניך בדרך בְכל עץ או על הארץ אפרחים או ביצים והאם רבצת על האפרחים או על הביצים לא תקח האם על הבנים שלח תשלח את האם ואת הבנים תקח לך למען ייטב לך והארכת ימים

If, along the road, you chance upon a bird’s nest thee in the way, in any tree or on the ground, with nestlings or eggs, and the mother sitting over the nestlings or on the eggs, do not take the mother with her young; you must surely let the mother go, but take only the young so that it may be well with you, and you may prolong your days.  (שביבי אש)

Deuteronomy 22:6

In the Midrash Rabbah it is written: This bears on the verse (Proverbs 4:23): “מכל משמר נצר לבך כי ממנו תוצאות חיים” (keep your heart with all vigilance, for from it flow the springs of life).

What is the connection between this verse and the commandment of sending away the mother before taking the nestlings? Our master explained that the Torah promises the same reward for fulfilling this commandment as for honoring one’s father and mother. Concerning both it says (Deuteronomy 22:7), “למען ייטב לך והארכת ימים (that it may go well with you, and that you may live long) (See also Deuteronomy 5:16)

But the Midrash (Deuteronomy Rabbah 6) finds it problematic that the reward for the two commandments is the same:

“אורח חיים פן תפלס” (She does not chart a path of life) (Proverbs 5:6). The honoring of parents is the weightiest commandment and its reward is long life . . . and the sending away of the mother bird is the least weighty, and what is its reward? Length of days.

It seems astonishing that both commandments should carry the same reward. But the problem may be explained as follows. If we should serve the Eternal in order to receive a reward, like a slave serving his master, then we shall all receive a reward commensurate with our service. The greater the service, the greater the reward. But we may also serve the Eternal as a son who serves his father, a son whose every longing is to give honor to his father and to carry out his wishes. If we serve the Eternal in this way, if our desires and longings are to serve Him in joy and gladness with no wish for any reward, then we shall all receive the same reward whether our service is great or small. For then the Eternal will treat us just as a father who, in dividing up his estate, does not distinguish among his children according to how much service they provided him, not giving a larger portion to a son who did more for him and a smaller one to a son who provided only a trifling service.

This is the meaning of the Midrash. The verse: “מכל משמר נצר לבך כי ממנו תוצאות חיים” (More than all that you guard, guard your heart, for it is the source of all life). What is the connection between the reward for honoring one’s parents with the reward for sending away the mother before taking the nestlings? It is clearly that it is the intent of our heart which is of greatest importance. What is essential is to direct our heart toward Heaven, for it is from Heaven that the longevity mentioned here is bestowed.

In this way one can explain what the Talmud says at the end of Hullin (142a). A man once told his son to bring him nestlings and the son went to the roof and brought the young birds from their nest and on his way down the son fell to his death. What happened, the Talmud asks, to the longevity that this one was promised for obeying his father and for sending away the mother before taking the nestlings? And the Talmud replies that perhaps he had been harboring idolatrous thoughts, by which the Talmud must have meant that the son did not perform the commandments with the proper intent, for the sake of the Eternal to give Him satisfaction, but instead performed them only for the sake of reward. And this improper intention was referred to metaphorically as “idolatrous,” because his intention was not to serve the Eternal, but to serve himself. And although the Eternal does provide a reward even to those who serve Him for the sake of a reward, the longevity promised in this verse relates only to those who serve Him from love.

Another answer that one might offer is that our Sages say that one who would offer a reason that the commandment of sending away the mother before taking the nestlings is instructed to keep silent. And this presumably applies to anyone who provides a reason for any of the commandments dictated by reason such as honoring one’s parents. The Talmud thus may have meant to say that perhaps the son fell to his death, because he had been thinking that he was performing these commandments out of mercy, and because he performed the commandments with that intention, his performance of them did not safeguard him against a fatal mishap. Perhaps this was also the meaning of the Midrash: “מכל משמר נצר לבך” (keep your heart with all vigilance). Do not think that we perform the commandments of the Eternal out of mercy. (שביבי אש)

The Talmud (Hullin 139a) states:

Our Rabbis taught: It is written (Deuteronomy 22:6): “כי יקרא קן צפור לפניך בדרך או על הארץ” (if, along the road, you chance upon a bird’s nest in any tree or on the ground). What does Scripture teach thereby? Because it is also written (Id. 22:7): “שלח תשלח את האם ואת הבנים תקח לך” (But you shall let the mother go, and take the young) I might suppose that one should go searching over mountains and hills to find a nest, the text therefore states: “כי יקרא” that is, if you happen upon.

From here the Havot Ya’ir (responsum no. 67) concluded that even if one does not want to take anything from the nest, there is an obligation to send away the mother and to take the children, for the Talmud deduced from this verse that “כי יקרא קן צפור” teaches us that one is not obligated to go searching for a nest in the mountains and hills in order to fulfill this obligation. I am amazed  by this statement, for the deduction of the Talmud is precisely that the formulation ” כי יקרא קן צפור ” teaches us that there is no unconditional obligation (as we might have thought from the repetition of the words” שלח תשלח” ) to seek a nest to be able to send the mother away. Only if the words “כי יקרא קן צפור” had not been written, would I have concluded that there is an absolute obligation to send away the mother and take the children. So it was precisely to preclude this inference that the Scripture wrote “כי יקרא קן צפור”. Even when one happens upon a nest, there is no obligation to send away the mother, unless one does want to take the children.

Now the Havot Yair bases his inference from the Talmud that there is an absolute obligation to send away the mother and to take the children on the explanation of this obligation given by the holy Zohar, which is that if the mother bird will be distraught and flies from one place to another in search of her children, the mother’s pain will arouse the pity of the Omnipresent, blessed be He, on his children in exile. But it is known that the kabalistic explanations are in many cases not in accord with the halakhah, as I have previously shown you in connection with the prohibition of the  “גיד הנשה” (sciatic nerve) which, according to the Zohar, is intended to repair the transgression of Jacob in marrying two sisters. For the sciatic nerve is one of the 365 sinews of the body, which correspond to the 365 negative prohibitions listed in the Torah. But this explanation accords only with the opinion of R. Judah who holds that prohibition of the sciatic nerve applies only to one of the sciatic nerves, but it does not accord with the opinion of the Sages who hold that the prohibition applies to both sciatic nerves. Similarly the kabalistic explanation for the tefilin to be worn on the weaker (left) hand, because the left hand is next to the heart, does not accord with the halakhah, because, according to this reason, a left-handed person should also wear the tefilin on his left hand. But in fact a left-handed person is required to wear the tefilin on his right hand. And there are many other instances in which the kabalistic explanation does not accord with the halakhah. (דור רביעי קל”ט ע”ב)