Is there a halacha that prohibits punching or slapping someone?

Question

I assume there must be a law against causing a person very mild physical injury, but I don't know what it is.

1) If the injury may cause enduring harm--like punching someone with the risk of breaking their bones--what are the laws?

2) What about if the injury is extremely unlikely to cause any lasting harm, like slapping someone?

3) Are there any exceptions for parents to slap their children?

BONUS: Are you allowed to be a boxer, and have this as part of your job?

Answer 1

This discussion is basically the entirety of Bava Kama. There's way too much to source directly, but I'll try to point to a couple things.

The source for Chovel (recently came up in a Daf Yomi Shiur for Kesuvos 32) is derived from the possuk that ossurs a shaliach beis din from adding to the malkus. Chazal point out that Beis Din is given the authority to wound only so far, and that if a shaliach commits an aveirah even by going over the permitted number of malkot, then everyone NOT approved by Beis Din is certainly forbidden from intentionally injuring another person.

Primary sources:

• Maimonides, Mishneh Torah, Hilchot Khovel u-Mazik

• Tur and Shulchan Aruch Choshen Mishpat chapters 420-424 - Chovel Bechaveiro

  1. A person may not volunteer to be injured - Beis Din does not consider a waiver of rights against intentional personal injury to be valid. (Maimonides, Mishneh Torah, Hilchot Khovel u-Mazik ch.5:11)
  2. Even slapping without any actual injury is liable to prosecution. This is specifically discussed and falls under the category of boshet, for which there is botha sliding scale (based upon the people involved in the offense) and set penalties (given for specific actions - slapping, boxing ears, uncovering a womans hair in public, etc.). Rambam Khu"M ch.3:8-end
  3. Permission to hit a minor child by a parent or teacher only extends for the purposes of educational discipline. As mentioned elsewhere on these forums, slapping a child (particularly an older one) is considered to fall under the category of Lifnei Eiver lo Titen Michshol, as the child is likely to be provoked into retaliation (which would be a serious Torah offense - Moed Katan 17a). Rambam Khu"M 4:19 says that a parent is obligated to reimburse any injury TO THEIR OWN CHILD, whether they are adults (paid immediately) or children (invested in property until they become adults).

BONUS: As mentioned in 1, Torah law does not recognize a voluntary waiver against personal injury. This means that boxing a fellow Jew is absolutely forbidden. (Fun Rashi on parshas shemos 2:14 - Dathan and Aviram were called risha'im merely for lifting their hands to strike! Sanhedrin 58b) However, their is a question about whether wounding a non-Jew is prosecutable to the same extent as a Jew. The possibility exists that such a waiver, for a non-Jew, might be binding, making it permitted to hit him. He would still be held liable for hitting you, however, since your corresponding waiver would be invalid. Mipnei darchei shalom, we tend to treat non-Jews and Jews in the public domin identically.

As @user6591 hinted at, there IS an exception written into halacha regarding accidental personal injury in specific circumstances where we expect the individual to be "out of his mind" - injury by a drunkard on Purim is the big one here. But that doesn't provide an exemption for proactively entering into a fight with a clear mind and the express intent to injure another person.

Chazal would likely not condone the Jewish boxer/MMA fighter, especially since it's a dangerous sport where you subject yourself directly to injury - a violation of Vinishmartem Me'od Linafshoseichem. This piece has a decent treatment of it.

To answer @msh210's objection: The Rambam's psak regarding providing a waiver is quoting the psak in the mishna at the end of the 8th perek in Bava Kama. Rabbi Akiva in a previous mishna in that same perek (where the psak is like him) brings this point up to prove that a "Chovel be'atzmo" is still chayiv for damaging himself, even though there is no payment of any of the five forms of nezek. Kal VeChomer someone damaging another "with permission" is still considered assur.