Gemara

Question (R. Yirmeyah): If Reuven pierced a Bechor's ear and he died, do we fine his son?

(If Reuven sold a Kena'ani slave to a Nochri, he goes free and Reuven must pay up to 10 times his value to redeem him.) If you will say that (if Reuven died,) we fine his son, we cannot learn to our case. Perhaps there is more stringent, for every day that the slave is with the Nochri, he cannot observe Mitzvos;

(If Reuven planned to do a Melachah during Chol ha'Mo'ed, when it will be permitted due to Davar ha'Avud (not doing it would cause a loss), Chachamim forbid him to do it on Chol ha'Mo'ed.) If you will say that (if Reuven died) we do not fine his son, we cannot learn to here (Bechor). Perhaps here is more lenient, for Reuven never actually transgressed.

Here, if the fine applies to the one who made the Mum, (after he dies) it does not apply to his son;

If the fine applies to the Bechor itself, it applies also to his son!

Answer (R. Zeira - Mishnah): If Reuven fertilized a field in Shemitah, he may not sow it the next year;

(R. Yosi b'Rebbi Chanina): If he died, his son may sow it the next year;

This shows that the fine applies to the one who transgressed, but not to his son.

(Abaye): If Reuven was Metamei another's Taharos and he died, his son is exempt.

Letter of the law, physically unperceivable damage is not considered damage. Chachamim fined the damagre to pay for it, but they did not fine his son.

Mo'ed Katan 12b (Mishnah): If intended to do a Melachah on Chol ha'Mo'ed, he suffers the loss.

Question (R. Yirmeyah): If Reuven left a Melachah for Chol ha'Mo'ed, and he died, do we fine his son?

If you will say that we fine the son of one who blemished a Bechor, perhaps that is because it is a Torah Isur (so we cannot learn to here).

If Chachamim fined the person (who sinned), he is not here;

If they fined the property, it is here!

Answer (R. Zeira): The Mishnah about Shemitah teaches that they fined the person.

Rishonim

Rambam (Hilchos Yom Tov 7:4): If one intentionally delayed his work until Chol ha'Mo'ed, and did it during the Mo'ed, Beis Din deprive him of it and make it Hefker to everyone. If he delayed his work until Chol ha'Mo'ed and he died, we do not fine his son or deprive him of it. We do not stop the son from doing it during the Mo'ed, lest it perish.

Magid Mishneh: The Gemara concluded that we fine only him, but not his son. The Rambam says that we make it Hefker to everyone. The Ramach says that the Ge'onim say that we leave it to perish and stop him from doing the Melachah, but we did not make it Hefker. The Ritz Gei'us brings from Rav Paltoy Matisyahu and R. Natrunai Ga'on that we make it Hefker. He did not mention another opinion. However, the Gemara connotes that this is like blemishing the ear or selling a slave to a Nochri. Surely regarding a Bechor, the only fine is not to slaughter it based on this Mum. For a slave, the fine is to redeem him for up to 10 times his value. However, the consensus of Ge'onim is like the Rambam. This is primary.

Nimukei Yosef (Mo'ed Katan 6b DH Mahu): If there is no property to fine, e.g. a tailor, weaver or scribe who works for others, we fine him himself. We excommunicate him until he accepts the law, and lash him.

Beis Yosef (OC 538 DH u'Chasuv): R. Yerucham says similarly in the name of R. Natrunai Ga'on.

Objection (Bedek ha'Bayis): Regarding a tailor, weaver or scribe, there is property to fine, i.e. his wages! Perhaps we discuss when he already received his wages and consumed them. What does it mean 'we excommunicate him until he accepts the law'? Perhaps it means that he returns his wages and gives them to Beis Din for them to dispose of. Also, what is the source to lash him? The Gemara says only that we deprive him of it. This suffices!

Answer (Kaf ha'Chayim 27, citing Machazik Berachah): We lash him until he accepts (not to do the Melachah); the Ritva and R. Yerucham say so.

Rosh (5:6): Why is the Ramban lenient about one who was chased by a Bechor and blemished it? This is a Safek Torah! Perhaps even though blemishing is an Isur Torah, the Isur to eat it due to the Mum is only mid'Rabanan.

Mishneh l'Melech (Hilchos Bechoros 4:1 DH v'Da she'Acher): The entire Sugya says that it is a fine not to eat the Bechor based on the Mum. If it were an Isur Torah, surely we would fine his son like himself! Abaye learned from here to one who was Metamei Taharos. Since both of these are only fines, we do not fine his son.

Poskim

Shulchan Aruch (OC 538:6): If Reuven planned to do Melachah during Chol ha'Mo'ed and did it then, Beis Din deprive him of it and make it Hefker to everyone.

Beis Yosef (DH ha'Mekaven): Rashi explains that if one planned to leave Melachah for Chol ha'Mo'ed, one may not benefit from it. The Rambam and Semag say that we make it Hefker. The Tur holds like the Ramach.

Kaf ha'Chayim (19): The case is, he could have done it before the Mo'ed, or waited until after the Mo'ed, but he intentionally started shortly before the Mo'ed.

Mishnah Berurah (17): If no one acquired it during the Mo'ed, Reuven may take it afterwards.

Kaf ha'Chayim (23): If he planned for Nochrim to do his work on Chol ha'Mo'ed, we do not fine him.

Kaf ha'Chayim (24): If he did not yet do the Melachah, it suffices to forbid him to do it. We need not make it Hefker.

Kaf ha'Chayim (25): Since many Rishonim hold that Meleches Chol ha'Mo'ed is mid'Rabanan, we cannot deprive one of his property due to Safek. Therefore, we do not fine his son. The son may finish it during the Mo'ed if it is Devar ha'Avud.

Rema: If he worked for others, and we cannot fine him, e.g. a tailor or scribe who works for others, we excommunicate him and lash him.

Mishnah Berurah (18): Eliyahu Rabah says that we deprive him of all his wages.

Gra (DH Meshamtinan): When the Mikdash stood, they would excommunicate him or lash him. I.e. they would lash a Chacham (whom we do excommunicate), like it says in OC 496:1. The Ran asked that in many places, they excommunicated (even when the Mikdash stood)! YD 334:43,44 mentions Aveiros for which we excommunicate a Chacham. We also find lashes mid'Rabanan (after the Churban), e.g. for cooking (on Yom Tov not for the need of Yom Tov - Pesachim 48a), Chulin 141b, and Kidushin 12b. It seems that one may do either (lash or excommunicate), like it says in Kidushin (perhaps this should say Pesachim 52a - PF). The Rema says 'or we excommunicate him', i.e. for others (not Chachamim).

Mishnah Berurah (19): We lash him until he agrees not to do the Melachah.

Shulchan Aruch: If he died, we do not fine his son. His son may do it if it is Devar ha'Avud.

Beis Yosef (DH u'Mah she'Chasav u'Mutar): According to the Tur (the fine is only to forbid doing the Melachah during the Mo'ed), surely the son may do it during the Mo'ed. Also the Rambam and Semag wrote that we do not fine the son at all. We let him do it during the Mo'ed, lest it perish. R. Yerucham cites Meforshim that only for Devar ha'Avud we do not fine the son, but if Reuven did Melachah that is not Devar ha'Avud during the Mo'ed, if he died we fine the son. R. Yerucham says that this is like the opinion that the Torah forbids Melachah during Chol ha'Mo'ed, so if it is not Devar ha'Avud, we fine his son. We say that if one blemished a Bechor, we fine his son, for it is an Isur Torah.

Beis Yosef (ibid.): R. Yerucham erred about one who blemished a Bechor. In Bechoros, we concluded that we do not fine his son! We infer from this that if one intended to do Melachah during Chol ha'Mo'ed, even if it is not Devar ha'Avud, we do not fine his son, for it is no more stringent than Meleches Chol ha'Mo'ed.

Taz (2): R. Yerucham and the Meforshim did not overlook an explicit Gemara. They are correct. In Mo'ed Katan, R. Yirmeyah asked whether we fine his son regarding Meleches Chol ha'Mo'ed. R. Zeira proved from Shemitah that we do not. In Bechoros, he asked whether we fine his son if the father blemished a Bechor and died. Why did he ask this, and not about leaving Melachah that is not Devar ha'Avud for Chol ha'Mo'ed, which is also mid'Oraisa? The Meforshim held that surely we fine his son in this case, for there are two reasons to be stringent. He planned Melachah for Chol ha'Mo'ed, and he did Melachah that is not Devar ha'Avud. This is true also in the conclusion. Regarding Shemitah we do not fine his son, for there is only one reason to be stringent, i.e. he did an Isur. R. Yerucham says that the Meforshim forbid Meleches Chol ha'Mo'ed mid'Oraisa, since they equated it to Bechor, and we fine his son, since there are two reasons to be stringent.

Mishbetzos Zahav: We can say that even though Chachamim did not fine his son regarding Bechor and Shemitah, which are mid'Oraisa, leaving Melachah for Chol ha'Mo'ed is worse, for he intended to sin and sinned. Beis Din make it Hefker to all, even if the Melachah was finished. The Mechaber discusses Devar ha'Avud. Do not infer that if it is not Devar ha'Avud, we deprive him of it. Perhaps he taught Devar ha'Avudaraham, for it is a Chidush, i.e. (if he did not intend to do it during the Mo'ed), it is permitted l'Chatchilah. The Prishah holds like the Taz. (We fine his son when there are two reasons.)

Magen Avraham (2): The Nimukei Yosef says that if one did Melachah during Chol ha'Mo'ed that is not Devar ha'Avud, we fine even his son, and we make him lose it. R. Yerucham says that this is like the opinion that forbids Meleches Chol ha'Mo'ed mid'Oraisa. I say that it is like Melachah on Shabbos. It is forbidden to him forever, and similarly to his son. See the beginning of Simanim 318 and 530. (Note: I did not find that they discuss fining the son.) This requires investigation from Gitin (53b) and YD 99.

Machatzis ha'Shekel: The Magen Avraham concludes that the reason to be stringent is because it is like Melachah on Shabbos, unlike R. Yerucham. We must explain why blemishing a Bechor is unlike Melachah on Shabbos.

Eshel Avraham: In Siman 530, the Rema says that Chachamim decided to forbid certain Melachos during Chol ha'Mo'ed. In Siman 537, we permit a Safek Devar ha'Avud, which suggests that Meleches Chol ha'Mo'ed is mid'Rabanan.

Eliyahu Rabah: The Shulchan Aruch and Levush connote that we do not fine his son even if it is not Devar ha'Avud. This is like the Beis Yosef's rejection of R. Yerucham. How did he overlook the Nimukei Yosef, who forbids Melachah that was not Devar ha'Avud?! This shows that we must distinguish. I say that since we fine him for Devar ha'Avud, which is mid'Rabanan, we must be more stringent about what is not Devar ha'Avud, which is a Torah Isur. Also, here there are two reasons to be stringent, like the Prishah and Taz say.

Mishnah Berurah (20): If someone else acquired it (from Hefker), the son does not inherit it. It seems that even if no one else acquired it, the son does not inherit it, but he can acquire from Hefker like anyone else. The Mechaber discusses when he died before Beis Din made it Hefker.

Mishnah Berurah (21): If the father did Melachah that is not Devar ha'Avud, some forbid to the son according to those who forbid Meleches Chol ha'Mo'ed mid'Oraisa, but the Beis Yosef and other Acharonim questioned this.

Bi'ur Halachah (DH Im): Some reject the answer for R. Yerucham, since for Melachah that is not Devar ha'Avud, what improper intent was there? The Beis Meir questioned the Magen Avraham. What is the source that food cooked on Shabbos is forbidden to the son? The Magen Avraham forbids to the one for whom it was cooked, but did he cook so his son will inherit it?! The Shulchan Aruch's opinion is primary.