The Gemara [Bava Kamma 15a] says:
דבי חזקיה ורבי יוסי הגלילי תנא אמר קרא (שמות כא, כט) והמית איש או אשה השוה הכתוב אשה לאיש לכל מיתות שבתורה
The school of Chizkiyya and Rabbi Yosei HaGlili taught: The verse states with regard to liability in a case where one’s ox kills a person: “And it killed a man or a woman” (Exodus 21:29). The verse thereby equates a woman with a man with regard to all killings in the Torah, i.e., the liability incurred is the same whether the person killed was a man or a woman.
Why do we need a pasuk to include that there is liability for killing a woman as well? We can derive this from the fact that we need a special pasuk to disqualify women from testifying [ועמדו שני אנשים - ולא נשים]. If one was פטור for killing a woman then no pasuk would be necessary to teach that women are פסולות לעדות because they would automatically be פסולות לעדות because ליתא בזוממי זוממין - meaning that if one testified that a woman killed they would be פטור if found to be עדים זוממין [from a קל וחומר - if for actually killing a woman one is פטור then certainly for conspiring to kill one]. If there is no דין of זממה then there is no דין עדות!! From the fact that we need a pasuk to teach that woman are פסולות לעדות it must be that there is a דין זממה and a person is חייב for killing a woman.
From this Rabbeinu Chaim proved his principle [that we already explicated in recent posts] that we don't equate actually killing [where one might not be חייב] and killing with עדות [where one is definitely חייב]. The מחשבה to kill is worse than the מעשה.
Maybe we can respond to this proof as follows: The Minchas Chinuch [מצוה ד] learns that for Kiddush Hachodesh we need עדים that can become זוממין.
This is subject to debate - The source for הזמה is the pasuk "ועשיתם לו כאשר זמם לעשות לאחיו" - You do to him as he conspired to do to his BROTHER! Kiddush Hachodesh is not "לאחיו" so no possibility of הזמה would seem necessary. [See תשובות רעק"א סימן קע"ו סייעתא לדברינו]. It would therefore appear that women are disqualified for testifying about the new moon [Kiddush Hachodesh 2-1] because of the pasuk ועמדו שני אנשים which excludes נשים, and not because we need עדות שאתה יכול להזימה. So it turns out that we need the pasuk of ועמדו שני אנשים to exclude women from testifying about the new moon and thus it furnishes no proof that it is forbidden to kill a woman.
[עפ"י הס' זאב יטרף]
From this Rabbeinu Chaim proved his principle [that we already explicated in recent posts] that we don't equate actually killing [where one might not be חייב] and killing with עדות [where one is definitely חייב]. The מחשבה to kill is worse than the מעשה.
Maybe we can respond to this proof as follows: The Minchas Chinuch [מצוה ד] learns that for Kiddush Hachodesh we need עדים that can become זוממין.
This is subject to debate - The source for הזמה is the pasuk "ועשיתם לו כאשר זמם לעשות לאחיו" - You do to him as he conspired to do to his BROTHER! Kiddush Hachodesh is not "לאחיו" so no possibility of הזמה would seem necessary. [See תשובות רעק"א סימן קע"ו סייעתא לדברינו]. It would therefore appear that women are disqualified for testifying about the new moon [Kiddush Hachodesh 2-1] because of the pasuk ועמדו שני אנשים which excludes נשים, and not because we need עדות שאתה יכול להזימה. So it turns out that we need the pasuk of ועמדו שני אנשים to exclude women from testifying about the new moon and thus it furnishes no proof that it is forbidden to kill a woman.
[עפ"י הס' זאב יטרף]
