שֶׁ֚בֶר תַּ֣חַת שֶׁ֔בֶר עַ֚יִן תַּ֣חַת עַ֔יִן שֵׁ֖ן תַּ֣חַת שֵׁ֑ן כַּאֲשֶׁ֨ר יִתֵּ֥ן מוּם֙ בָּֽאָדָ֔ם כֵּ֖ן יִנָּ֥תֶן בּֽוֹ׃
Bruch um Bruch, Aug‘ um Auge, Zahn um Zahn, die Verletzung, die er einem Menschen beigebracht, werde auch ihm beigebracht.
Mekhilta d'Rabbi Yishmael
(Exodus 21:15) "And if one strikes his father and his mother, he shall be put to death": What is the intent of this? Because it is written (Leviticus 24:20) "an eye for an eye, etc.", and Scripture took it (striking father or mother) out of its category to make it more stringent, to make it liable to the death penalty, this section was, therefore, stated.