(טז) וְאֵ֣ת ׀ שְׂעִ֣יר הַֽחַטָּ֗את דָּרֹ֥שׁ דָּרַ֛שׁ מֹשֶׁ֖ה וְהִנֵּ֣ה שֹׂרָ֑ף וַ֠יִּקְצֹ֠ף עַל־אֶלְעָזָ֤ר וְעַל־אִֽיתָמָר֙ בְּנֵ֣י אַהֲרֹ֔ן הַנּוֹתָרִ֖ם לֵאמֹֽר׃
(16) Then Moses inquired about the goat of sin offering, and it had already been burned! He was angry with Eleazar and Ithamar, Aaron’s remaining sons, and said...


Therefore, Adam the first manwas created alone, to teach you that with regard to anyone who destroys one soul from the Jewish people, i.e., kills one Jew, the verse ascribes him blame as if he destroyed an entire world, as Adam was one person, from whom the population of an entire world came forth. And conversely, anyone who sustains one soul from the Jewish people, the verse ascribes him credit as if he sustained an entire world.
לְפִיכָךְ נִבְרָא אָדָם יְחִידִי, לְלַמֶּדְךָ, שֶׁכָּל הַמְאַבֵּד נֶפֶשׁ אַחַת מִיִּשְׂרָאֵל, מַעֲלֶה עָלָיו הַכָּתוּב כְּאִלּוּ אִבֵּד עוֹלָם מָלֵא. וְכָל הַמְקַיֵּם נֶפֶשׁ אַחַת מִיִּשְׂרָאֵל, מַעֲלֶה עָלָיו הַכָּתוּב כְּאִלּוּ קִיֵּם עוֹלָם מָלֵא.
(יא) כִּ֣י נֶ֣פֶשׁ הַבָּשָׂר֮ בַּדָּ֣ם הִוא֒
(11) For the life of the flesh is in the blood...
(כא) וַיֹּאמְר֞וּ אִ֣ישׁ אֶל־אָחִ֗יו אֲבָל֮ אֲשֵׁמִ֣ים ׀ אֲנַ֘חְנוּ֮ עַל־אָחִ֒ינוּ֒ אֲשֶׁ֨ר רָאִ֜ינוּ צָרַ֥ת נַפְשׁ֛וֹ בְּהִתְחַֽנְנ֥וֹ אֵלֵ֖ינוּ וְלֹ֣א שָׁמָ֑עְנוּ עַל־כֵּן֙ בָּ֣אָה אֵלֵ֔ינוּ הַצָּרָ֖ה הַזֹּֽאת׃ (כב) וַיַּ֩עַן֩ רְאוּבֵ֨ן אֹתָ֜ם לֵאמֹ֗ר הֲלוֹא֩ אָמַ֨רְתִּי אֲלֵיכֶ֧ם ׀ לֵאמֹ֛ר אַל־תֶּחֶטְא֥וּ בַיֶּ֖לֶד וְלֹ֣א שְׁמַעְתֶּ֑ם וְגַם־דָּמ֖וֹ הִנֵּ֥ה נִדְרָֽשׁ׃
(21) They said to one another, “Alas, we are being punished on account of our brother, because we looked on at his anguish, yet paid no heed as he pleaded with us. That is why this distress has come upon us.” (22) Then Reuben spoke up and said to them, “Did I not tell you, ‘Do no wrong to the boy’? But you paid no heed. Now comes the reckoning for his blood.”
"A process is unfolding in which his blood נִדְרָֽשׁ..."
"His blood" is the subject of this phrase. The verbal element here is a participle in the niphal binyan; and in fact, this is the only occurrence of this form of this verb in Tanakh (although this verbal root appears hundreds of times altogether in Tanakh).
to allow oneself to be enquired of, consulted (only of God), to be sought, be sought out, to be required (of blood)
(ח) וַיֹּ֥אמֶר קַ֖יִן אֶל־הֶ֣בֶל אָחִ֑יו וַֽיְהִי֙ בִּהְיוֹתָ֣ם בַּשָּׂדֶ֔ה וַיָּ֥קׇם קַ֛יִן אֶל־הֶ֥בֶל אָחִ֖יו וַיַּהַרְגֵֽהוּ׃ (ט) וַיֹּ֤אמֶר יהוה אֶל־הַ֔יִן אֵ֖י הֶ֣בֶל אָחִ֑יךָ וַיֹּ֙אמֶר֙ לֹ֣א יָדַ֔עְתִּי הֲשֹׁמֵ֥ר אָחִ֖י אָנֹֽכִי׃ (י) וַיֹּ֖אמֶר מֶ֣ה עָשִׂ֑יתָ ק֚וֹל דְּמֵ֣י אָחִ֔יךָ צֹעֲקִ֥ים אֵלַ֖י מִן־הָֽאֲדָמָֽה׃
(8) Cain said to his brother Abel … and when they were in the field, Cain set upon his brother Abel and killed him. (9)יהוה said to Cain, “Where is your brother Abel?” And he said, “I do not know. Am I my brother’s keeper?” (10) “What have you done? Hark, your brother’s blood cries out to Me from the ground!
