1) THE PROSECUTION OF YOAV
QUESTION: After the death of David ha'Melech, Shlomo ha'Melech sought to bring Yoav to justice. He sent Benaiyahu to administer the punishment that Yoav deserved. Yoav fled into the Beis ha'Mikdash and grasped the corners of the Mizbe'ach. He refused to leave until Shlomo ha'Melech agreed that if he kills Yoav, he will accept upon himself the curse that was intended for Yoav's family.
The Gemara says that when Shlomo agreed, they brought Yoav to Beis Din to judge him for killing Avner and Amasa. The Gemara says that Yoav found a way to exempt himself from liability for the death of Avner, but the Gemara gives no defense for his killing of Amasa. The Gemara leaves us with the understanding that Yoav was found guilty for killing Amasa. However, TOSFOS points out that Yoav was exempt from liability in that case as well, because he did not receive proper Hasra'ah, warning from witnesses. Shlomo ha'Melech killed Yoav nonetheless, because of a third charge; he showed that Yoav was a "Mored b'Malchus" -- he had rebelled against the kingship of Shlomo's father, David ha'Melech.
If Shlomo ha'Melech wanted to charge Yoav for being "Mored b'Malchus," then why did he first try to prosecute him with charges of murder? Why did he not immediately charge him with being "Mored b'Malchus"?
Moreover, why did Shlomo ha'Melech accept Yoav's curse if he was able to prosecute him and kill him as a "Mored b'Malchus"? If, for someone reason, Shlomo ha'Melech was not able to kill Yoav for being "Mored b'Malchus," then why did Yoav agree to forfeit his life if Shlomo ha'Melech would accept the curse?
ANSWER: The MARGOLIYOS HA'YAM cites the TESHUVOS BEN YEHUDAH (#20) who explains Shlomo's actions based on the words of the RAMBAM (Hilchos Rotze'ach 5:14). The Rambam rules that the Mizbe'ach does not protect a person who is Chayav Misah because of a sin. Even if a person kills b'Shogeg, accidentally, and is thus obligated to be sent to Galus to an Ir Miklat, the Mizbe'ach does not protect him unless he is a Kohen who is performing the Avodah on the Mizbe'ach. However, if the king wants to kill a person (based on the king's power to execute a person), or if Beis Din wants to kill a person based on a "Hora'as Sha'ah" (to teach a lesson and not based on actual Din Torah), and the person flees to the Mizbe'ach, the Mizbe'ach protects him and he cannot be killed unless the court proves -- based on the testimony of valid witnesses -- that he is Chayav Misah for a sin that he committed.
The KESEF MISHNEH asks that according to the Rambam, how was Shlomo ha'Melech able to kill Yoav? Tosfos says that Yoav was not proven by Beis Din to be Chayav Misah for a sin, but rather he was Chayav Misah only because of the Din Malchus -- the right of the king to execute a person!
The Teshuvos Ben Yehudah answers that this is why Shlomo ha'Melech first accused Yoav of being Chayav Misah for killing Avner and Amasa. He wanted to use the court case for that crime as a pretext to remove Yoav from the Mizbe'ach.
How did this tactic work? If Beis Din found that Yoav was not guilty of the charges that Shlomo ha'Melech brought against him, then they should have returned Yoav safely to the Mizbe'ach!
The answer may be as follows. Had Yoav been found innocent, perhaps they would have returned him to the Mizbe'ach. However, although he was not found guilty of killing b'Mezid, he was found guilty of killing b'Shogeg, and thus he was Chayav Galus -- he was obligated to be sent to an Ir Miklat. Now Yoav was trapped: if he would demand to be returned to the Mizbe'ach, Shlomo ha'Melech could not kill him as a "Mored b'Malchus." However, Yoav could be killed by the Go'el ha'Dam because of his status of a Rotze'ach b'Shogeg. Since Shlomo ha'Melech was Amasa's first cousin, Shlomo had the status of Amasa's Go'el ha'Dam and thus he could kill Yoav. On the other hand, if Yoav would demand that the court bring him to an Ir Miklat, he would be safe from the Go'el ha'Dam but Shlomo ha'Melech could kill him as a "Mored b'Malchus."
Yoav decided that he would prefer to stay with the Mizbe'ach, because he knew that the king would feel uncomfortably personally coming and killing someone himself as a Go'el ha'Dam. Benaiyahu had to obtain Yoav's permission to remove Yoav from the Mizbe'ach in order to spare Shlomo ha'Melech the embarrassment of having to come in personally to kill Yoav with his own hands (since the Go'el ha'Dam may not send a Shali'ach to do his work). Yoav agreed to leave if Shlomo ha'Melech would accept his curse, because he realized that even if he would stay at the Mizbe'ach, he still could be killed by Shlomo ha'Melech who was the Go'el ha'Dam of Amasa, and therefore he would not escape death by refusing to leave. (See the MARGOLIYOS HA'YAM #5.)
2) INTERRUPTING ONE'S LEARNING IN ORDER TO FULFILL THE COMMAND OF THE KING
QUESTION: The Gemara says that Amasa was correct in disobeying the king's order and not garnering the soldiers within three days, because he found them involved in learning. He derived from a verse that one should not interrupt one's Torah learning even to follow the command of a king. This implies that learning Torah is more important that following the command of a king.
A similar principle is taught in Megilah (17a), where the Gemara derives from Yakov's extended stay in the Yeshiva of Shem v'Ever that learning Torah overrides one's obligation of Kibud Av v'Em, honoring one's parents.
How can this idea be reconciled with the Gemara in Moed Katan (9a; see Insights there, #2) that states that a Mitzvah which cannot be fulfilled by another person overrides the Mitzvah of Talmud Torah? A person is supposed to stop learning in order to fulfill such a Mitzvah. It is clear from the Gemara here that when the soldiers who were learning did not come, there was no one else to take their place. Why, then, did Amasa not interrupt their learning to fulfill the command of the king? (NACHALAS SHIMON, Shmuel II 36:2)
ANSWERS:
(a) The ME'IRI here writes that Amasa did not disturb the soldiers because it was a matter of public Torah learning, Talmud Torah d'Rabim. With regard to Kibud Av v'Em, the Gemara in Megilah is not discussing a situation in which the father actually commanded the son to do something for him. Rather, it is discussing whether it is a greater Mitzvah to learn Torah even though one thereby will not have the opportunity to fulfill the Mitzvah of Kibud Av v'Em while he is learning. In such a case, Talmud Torah is considered a greater Mitzvah than having the opportunity to fulfill the Mitzvah of Kibud Av v'Em. If, however, the parents need something or ask for something specific, then the Mitzvah of Kibud Av v'Em overrides Talmud Torah.
A similar distinction is expressed by the PISCHEI TESHUVAH (YD 240:8) in the name of the PRI CHADASH. He writes that Talmud Torah is greater than Kibud Av v'Em, and for that reason a person should go to the place where he can learn best, even if it is far from the city of his parents and he will not be able to tend to, or even be aware of, his parents' needs. He adds that even if one's father or mother insists that one not travel to a certain place to learn Torah because of the risk of violence from the Nochrim in that location, the son is not required to listen to them but may travel to where he feels he will learn best. The father's command to the son that he not learn Torah in the best way does not override the son's obligation to learn Torah in the best way. However, if the son is learning in the city of his father, then he is required to tend to his father's needs and learn only when his father does not need him. In that case, Kibud Av v'Em is a Mitzvah which cannot be fulfilled by another person and thus it overrides Talmud Torah.
(b) The CHACHAM TZVI (#38, cited by the Nachalas Shimon) distinguishes between Mitzvos that are objectively obligatory and Mitzvos that are subject to the will of a person. Since the Mitzvah to heed the words of a king, or the words of one's parent, is subject to the king's or parent's will, and he could just as easily not make his request and not obligate others to follow his will, such a Mitzvah does not override the Mitzvah of Talmud Torah. The Gemara in Kesuvos (40a) is a source for such a distinction. The Gemara there says that the Mitzvas Aseh for a rapist to marry his Anusah does not override a Lo Ta'aseh if she is prohibited to him with a Lav. Since the woman has the right to forgo marrying the man, it is a Mitzvah that is subject to a person's will and such a Mitzvah cannot override a Lo Ta'aseh, as the RAN and RASHBA (Teshuvos 1:10) explain.
The TUREI EVEN in Megilah (29a) makes a similar distinction.
According to this approach, if the king or parent has an objective need for something and does not make a request based on his own will (such as when a king or parent is sick and needs medicine and treatment), then caring for the king or parent overrides Talmud Torah. When the needs of the king or parent are not objective (such as in the case of the Gemara here, when David ha'Melech insisted on assembling the soldiers within three days, even though it was not a life-and-death necessity to gather them that quickly (because if it was a matter of Piku'ach Nefesh, it certainly would have been Docheh all other Mitzvos)), those needs do not override the Mitzvah of Talmud Torah.
3) HOW YOAV WAS ABLE TO KILL AVNER
QUESTION: Rebbi Yochanan says that before Yoav killed Avner, "he judged him with the judgment of Sanhedrin." Yoav proved to Avner that according to the Halachah, his act of killing Asah'el was considered murder, since he could have injured Asah'el instead and saved himself that way. That entitled Yoav, as the Go'el ha'Dam of Asah'el, to kill Avner. (Even if Avner did not receive Hasra'ah and could not be killed in court, he was no less than a Rotze'ach who kills accidentally, whom the Go'el ha'Dam is permitted to kill.)
The Gemara proceeds to relate how Yoav fooled Avner. Yoav asked Avner how a woman with no arms can perform the procedure of Chalitzah by removing the Yavam's shoe. Avner told him that the woman can do it with her teeth. When Avner bent down to demonstrate how one can remove a shoe with one's teeth, Yoav drew his sword and killed Avner.
If Yoav proved to Avner that he was not justified in killing Asah'el and thus Yoav was entitled to act as a Go'el ha'Dam, then how did Avner fall for Yoav's trick and let down his guard to let Yoav kill him? He knew that Yoav was the Go'el ha'Dam of Asah'el and thus he should have stayed as far away from Yoav as possible!
ANSWER: Perhaps the reason why Avner let down his guard is that the verse says that this interaction between Yoav and Avner occurred in the city of Chevron (Shmuel II 3:27). Chevron was an Ir Miklat, as the verse states in Yehoshua (21:11). Avner was not afraid of Yoav, the Go'el ha'Dam, because he was in an Ir Miklat, and a Go'el ha'Dam is not allowed to kill in an Ir Miklat.
If, however, they were in an Ir Miklat, then why indeed did Yoav kill Avner? Why was Yoav not Chayav Misah for doing so (since a Go'el ha'Dam who kills in an Ir Miklat is Chayav Misah)?
The answer may be learned from the words of the RAMBAM (Hilchos Rotze'ach 6:4) who distinguishes between a person who kills b'Shogeg, accidentally, and a person who kills in a manner that is close to Mezid, that is almost deliberate (such as when the killing was a result of the killer's negligence). The latter killer does not go to an Ir Miklat, and if he does flee to an Ir Miklat, the Ir Miklat does not protect him and the Go'el ha'Dam is entitled to kill him even in the Ir Miklat.
Avner killed Asah'el intentionally, but he did not receive Hasra'ah. Even if he was not aware of the Halachah that one is supposed to injure his pursuer when possible rather than kill him, such a misunderstanding of the Halachah would be considered a Peshi'ah, an act of negligence, since an act done by accident due to a lack of knowledge is considered an act done intentionally ("Shigegas Talmud Oleh Zadon").
Avner did not know that an Ir Miklat would not protect a person in his situation. Yoav took advantage of this Halachah, and Avner's lack of familiarity with it, to kill Avner in Chevron. (See MARGOLIYOS HA'YAM 49a:4 in the name of KAPEI AHARON.)

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