||you must cut off her hand [if necessary, to save her victim] and not have any pity.
Vekatsotah et-kapah lo tachos eynecha.
||You must not keep in your pouch two different weights, one large and one small.
Lo-yiheyeh lecha bechischa even va'aven gedolah uktanah.
||[Similarly], you must not keep in your house two different measures, one large and one small.
Lo-yiheyeh lecha beveytcha eyfah ve'eyfah gedolah uktanah.
(Sifri; Yad, Rotze'ach 1:7,8). The same is true in any case where a person is attacking another with deadly intent. Anyone witnessing the act must maim or kill the assailant to save the victim (Ibid.).
According to others, however, it is speaking of a case where the woman has no deadly intent, and 'cutting off her hand' denotes that she must pay for the humiliation she caused her victim (Bava Kama 27a; Rashi). Some translate it, 'You shall reckon the cost of her act (hand)' (HaKethav VeHaKabbalah).
|and not have any pity|
This is a negative commandment, not to have pity on an assailant (Sefer HaMitzvoth, Negative 293).
|You must not keep|
See Leviticus 19:35,36. See Ezekiel 45:10-12, Micah 6:11, Proverbs 11:1.
(Targum Yonathan; Septuagint). Kis in Hebrew. Or, 'Place of scales' (Ibn Ezra; Tur).
(cf. HaKethav VeHaKabbalah).