Negative commandment · Lo Ta’aseh #279 of 613
To not show pity upon the killer or injurer
שלא לרחם על המזיק בדיני קנסות
The verse · Devarim 25:12
וְקַצֹּתָה אֶת־כַּפָּהּ לֹא תָחוֹס עֵינֶךָ
“then thou shalt cut off her hand, thy eye shall not pity her.”
The Rambam’s words
Not to have pity on a person who has caused damages in judgments concerning fines, as [Deuteronomy 25:12] states: "Let your eye not pity."
שלא לרחם על המזיק בדיני קנסות, שנאמר "לֹא תָחוֹס עֵינְךָ" (דברים יט, כא).
Why · Sefer HaChinuch #521
To not show pity upon the killer or injurer
“The root of this commandment is well-known — that if we do not punish the injurers and purge the evil from among us, “a man will swallow his neighbor alive”; and states will not be [properly] civilized.”
Who & when
“And this prohibition is practiced at the time of the [Temple] by males, as it is upon them to administer justice.”
Where in the Mishneh Torah
Hilchot The Sanhedrin and the Penalties within Their Jurisdiction הלכות סנהדרין והעונשין המסורין להם