4:15ד׳:ט״ו
1 א

לכן כל הורג קין. זֶה אֶחָד מִן הַמִּקְרָאוֹת שֶׁקִּצְּרוּ דִּבְרֵיהֶם וְרָמְזוּ וְלֹא פֵרְשׁוּ, לָכֵן כָּל הֹרֵג קַיִן לְשׁוֹן גְּעָרָה, כֹּה יֵעָשֶׂה לוֹ, כָּךְ וְכָךְ עָנְשׁוֹ וְלֹא פֵּרֵשׁ עָנְשׁוֹ:

לכן כל הרג קין VERILY, WHOSOEVER SLAYETH CAIN — This is one of the verses where the construction is elliptical (literally, which abbreviate their statements), which give only a suggestion and do not fully explain. “Verily, whosoever slayeth Cain” express a threat, suggesting the consequence — “thus shall be done to him”, “thus and thus shall be his punishment”, without explicitly explaining what the punishment would be.

2 ב

שבעתים יקם. אֵינִי רוֹצֶה לְהִנָּקֵם מִקַּיִן עַכְשָׁו, לְסוֹף שִׁבְעָה דוֹרוֹת אֲנִי נוֹקֵם נִקְמָתִי מִמֶּנּוּ, שֶׁיַּעֲמֹד לֶמֶךְ מִבְּנֵי בָּנָיו וְיַהַרְגֵהוּ, וְסוֹף הַמִּקְרָא שֶׁאָמַר שִׁבְעָתַיִם יֻקָּם, וְהִיא נִקְמַת הֶבֶל מִקַּיִן, לִמְּדָנוּ שֶׁתְּחִלַּת מִקְרָא לְשׁוֹן גְּעָרָה הִיא, שֶׁלֹּא תְהֵא בְרִיָּה מַזִּיקַתּוּ, וְכַיּוֹצֵא בוֹ וַיֹּאמֶר דָּוִד כָּל מַכֵּה יְבֻסִי וְיִגַּע בַּצִּנּוֹר (שמואל ב ה'), וְלֹא פֵּרֵשׁ מַה יֵּעָשֶׂה לוֹ, אֲבָל דִּבֵּר הַכָּתוּב בְּרֶמֶז כָּל מַכֵּה יְבֻסִי וְיִגַּע בַּצִּנּוֹר וְיִקְרַב אֶל הַשַּׁעַר וְיִכְבְּשֶׁנּוּ וְאֶת הָעִוְרִים וגו', וְגַם אוֹתָם יַכֶּה עַל אֲשֶׁר אָמְרוּ הָעִוֵּר וְהַפִּסֵּחַ לֹא יָבֹא דָוִד אֶל תּוֹךְ הַבַּיִת – הַמַּכֶּה אֶת אֵלּוּ אֲנִי אֶעֱשֶׂנּוּ רֹאשׁ וְשַׂר, כָּאן קִצֵּר דְּבָרָיו, וּבְדִבְרֵי הַיָּמִים פֵּרֵשׁ יִהְיֶה לְרֹאשׁ וּלְשָׂר:

שבעתים יקם VENGEANCE SHALL BE TAKEN SEVENFOLD — God says, I do not wish to take vengeance on Cain now, but at the end of seven generations I will execute my vengeance upon him, that Lamech, one of his descendants, will arise and slay him. The end of this verse which states, “vengeance shall be taken in the seventh generation” — which is the vengeance taken on Cain for Abel — teaches us that the first part of the verse is a threat made in order that no creature might injure him. A similar elliptical expression is the following: (2 Samuel 5:8) “And David said, whosoever smiteth the Jebusites and getteth up to the gutter” — but it does not explicitly state what would be done to that person. Scripture, however, here speaks by a suggestion only, meaning, whosoever smiteth the Jebusites and getteth up to the gutter and approacheth the gate and conquereth it and the blind etc. … slaying also them (the blind and the lame) because they said, “there are the blind and the lame: David cannot come into the house” — he who smiteth these, I shall make him chief and captain. Here (in the Book of Samuel) it abridges the narrative, but in Chronicles (1 Chronicles 11:6) it explicitly states, “he shall become chief and captain.”

3 ג

וישם ה' לקין אות. חָקַק לוֹ אוֹת מִשְּׁמוֹ בְּמִצְחוֹ. ס"א דָּבָר אַחֵר, כָּל מוֹצְאִי יַהַרְגֵנִי, הַבְּהֵמוֹת וְהַחַיּוֹת, אֲבָל בְּנֵי אָדָם עֲדַיִן לֹא הָיוּ שֶׁיִּירָא מֵהֶם, רַק אָבִיו וְאִמּוֹ, וּמֵהֶם לֹא הָיָה יָרֵא שֶׁיַּהַרְגוּהוּ, אֶלָּא אָמַר עַד עַכְשָׁו הָיָה פַּחְדָּתִי עַל כָּל הַחַיּוֹת כְּמֹ"שֶׁ וּמוֹרַאֲכֶם וְגוֹ', וְעַכְשָׁו בִּשְׁבִיל עָוֹן זֶה לֹא יִירְאוּ מִמֶּנִּי הַחַיּוֹת וְיַהַרְגוּנִי, מִיָּד וַיָּשֶׂם ה' לְקַיִן אוֹת – הֶחֱזִיר אֶת מוֹרָאוֹ עַל הַחַיּוֹת:

וישם ה' לקין אות AND THE LORD SET A SIGN FOR CAIN — He inscribed on his forehead a letter of His Divine Name (Pirkei DeRabbi Eliezer 21). Other editions of Rashi add the following: another interpretation of “Whoever will find me will slay me”: this refers to cattle and beasts, since there were then no human beings in the world of whom he might be afraid except his father and mother, and, of course, he did not fear that they would slay him. He, therefore, said, “Until now the fear of me was upon all animals — as it is written”, (Genesis 9:2) “And the fear of you shall be upon all beasts of the field” etc. — now, however, because of my sin the animals will no longer fear me and will kill me. God immediately set a sign for Cain, viz., he again made the animals be in fear of him.