Ramban on Leviticus 19:18:1

וְטַעַם וְאָהַבְתָּ לְרֵעֲךָ כָּמוֹךָ הַפְלָגָה, כִּי לֹא יְקַבֵּל לֵב הָאָדָם שֶׁיֶּאֱהֹב אֶת חֲבֵרוֹ כְּאַהֲבָתוֹ אֶת נַפְשׁוֹ. וְעוֹד שֶׁכְּבָר בָּא רַבִּי עֲקִיבָא וְלִמֵּד, חַיֶּיךָ קוֹדְמִין לְחַיֵּי חֲבֵרְךָ (ב"מ סב). אֶלָּא מִצְוַת הַתּוֹרָה שֶׁיֹּאהַב חֲבֵרוֹ בְּכָל עִנְיָן כַּאֲשֶׁר יֹאהַב אֶת נַפְשׁוֹ בְּכָל הַטּוֹב. וְיִתָּכֵן בַּעֲבוּר שֶׁלֹּא אָמַר "וְאָהַבְתָּ אֶת רֵעֲךָ כָּמוֹךָ" וְהִשְׁוָה אוֹתָם בְּמִלַּת "לְרֵעֲךָ", וְכֵן "וְאָהַבְתָּ לוֹ כָּמוֹךָ" (ויקרא י"ט:ל"ד) דְּגֵר, שֶׁיִּהְיֶה פֵּרוּשׁוֹ לְהַשְׁווֹת אַהֲבַת שְׁנֵיהֶם בְּדַעְתּוֹ, כִּי פְּעָמִים שֶׁיֹּאהַב אָדָם אֶת רֵעֵהוּ בִּדְבָרִים יְדוּעִים, לְהֵטִיבוֹ בְּעֹשֶׁר וְלֹא בְּחָכְמָה וְכַיּוֹצֵא בָּזֶה, וְאִם יִהְיֶה אוֹהֲבוֹ בַּכֹּל, יַחְפֹּץ שֶׁיִּזְכֶּה רֵעֵהוּ הָאָהוּב לוֹ בְּעֹשֶׁר וּבִנְכָסִים וְכָבוֹד וּבְדַעַת וּבְחָכְמָה, וְלֹא שֶׁיִּשְׁוֶה אֵלָיו אֲבָל יִהְיֶה חָפֵץ בְּלִבּוֹ לְעוֹלָם שֶׁיִּהְיֶה הוּא יוֹתֵר מִמֶּנּוּ בְּכָל טוֹבָה. וִיצַוֶּה הַכָּתוּב שֶׁלֹּא תִּהְיֶה פְּחִיתוּת הַקִּנְאָה הַזֹּאת בְּלִבּוֹ, אֲבָל יֹאהַב בִּרְבוֹת הַטּוֹבָה לַחֲבֵרוֹ כַּאֲשֶׁר אָדָם עוֹשֶׂה לְנַפְשׁוֹ, וְלֹא יִתֵּן שִׁעוּרִין בָּאַהֲבָה. וְעַל כֵּן אָמַר בִּיהוֹנָתָן (שמואל א כ יז), "כִּי אַהֲבַת נַפְשׁוֹ אֲהֵבוֹ", בַּעֲבוּר שֶׁהֵסִיר מִדַּת הַקִּנְאָה מִלִּבּוֹ וְאָמַר (שם כג יז) "וְאַתָּה תִּמְלֹךְ עַל יִשְׂרָאֵל" וְגוֹ'. וְעִנְיַן הַנְּקִימָה וְהַנְּטִירָה כְּבָר פֵּרְשׁוּהוּ רַבּוֹתֵינוּ (תו"כ קדושים ד י יא), שֶׁהוּא בְּדָבָר שֶׁאֵין בּוֹ חִיּוּב מָמוֹן, הַשְׁאִילֵנִי מַגָּלְךָ, הַשְׁאִילֵנִי קַרְדֻּמְּךָ, כִּי בְּדָבָר שֶׁנִּתְחַיֵּב לוֹ חֲבֵרוֹ מָמוֹן כְּגוֹן בִּנְזִיקִין וְכַיּוֹצֵא בָּהֶן, אֵינוֹ מְחֻיָּב לְהַנִּיחַ לוֹ, אֲבָל יִתְבָּעֶנּוּ בְּב"ד וִישֻׁלַּם מִמֶּנּוּ, מִפָּסוּק "כַּאֲשֶׁר עָשָׂה כֵּן יֵעָשֶׂה לּוֹ" (ויקרא כ"ד:י"ט), וְהוּא מֵעַצְמוֹ חַיָּב לְשַׁלֵּם כַּאֲשֶׁר יְשַׁלֵּם מַה שֶׁלָּוָה אוֹ מַה שֶׁגָּזַל. וְכָל שֶׁכֵּן בְּעִנְיַן נֶפֶשׁ, שֶׁיִּהְיֶה נוֹקֵם וְנוֹטֵר לוֹ עַד שֶׁיִּגְאַל דְּמֵי אָחִיו מִיָּדוֹ עַל פִּי בֵּית דִּין הַמּוֹרִים בְּמִשְׁפְּטֵי הַתּוֹרָה: AND THOU SHALT LOVE THY NEIGHBOR AS THYSELF. This is an expression by way of overstatement, for a human heart is not able to accept a command to love one’s neighbor as oneself. Moreover, Rabbi Akiba has already come and taught,⁸⁶Baba Metzia 62 a. This teaching applies to a case where “two people are together on a journey and one has a pitcher of water; if they both drink from it they will die, because there is not enough for both, but if only one will drink he will survive. Ben Petura taught that it is better that both should drink and die, rather than that one should see the death of the other. [This was held to be the law] until Rabbi Akiba came and taught: that thy brother may live with thee (further, 25:36), thy life takes precedence over the life of thy brother.” “Your life takes precedence over the life of your fellow-being.” Rather, the commandment of the Torah means that one is to love one’s fellow-being in all matters, as one loves all good for oneself.⁸⁷Thus: “he is to speak in praise of his neighbor, and be as careful of his neighbor’s property as he is careful of his own property, and be as solicitous of his neighbor’s honor as he is of his own” (Rambam, Mishneh Torah, Hilchoth Mada, 6:3). It is possible that since it does not say “and thou shalt love ‘eth rei’acha’⁸⁸In that case the command would have been to love the person of one’s neighbor as much as one loves one’s own self. But instead the verse says l’rei’acha, which means “to [or ‘for’] your neighbor,” thus teaching that that which is good “for” your neighbor you should love as if it were good for youself. as thyself,” but instead it likened them in the word ‘l’rei’acha’ [which literally means “to” thy neighbor], and similarly it states with reference to a proselyte, and thou shalt love ‘lo’ (him) [but literally: “to” him] as thyself,⁸⁹Further, Verse 34. Here too the thought conveyed is: “that which is good for the proselyte you should love, as if it were good for your own self.” that the meaning thereof is to equate the love of both [himself and his neighbor, or himself and the proselyte] in his mind. For sometimes a person will love his neighbor in certain matters, such as doing good to him in material wealth but not with wisdom and similar matters. But if he loves him completely, he will want his beloved friend to gain riches, properties, honor, knowledge and wisdom. However [because of human nature] he will still not want him to be his equal, for there will always be a desire in his heart that he should have more of these good things than his neighbor. Therefore Scripture commanded that this degrading jealousy should not exist in his heart, but instead a person should love to do abundance of good for his fellow-being as he does for himself, and he should place no limitations upon his love for him. It is for this reason that it is said of Jonathan’s [love for David], for he loved him as he loved his own soul,⁹⁰I Samuel 20:17. because Jonathan had removed [altogether] the attribute of jealousy from his heart, and he said [to David], and thou shalt be king over Israel,⁹¹Ibid., 23:17. etc.
Our Rabbis have already explained⁹²Sifra, Kedoshim 4:10-11. the matters of taking vengeance and guarding a grudge [which are here forbidden], that they apply to cases where there is no monetary obligation, such as, “Lend me your sickle, lend me your hatchet.”⁹³If he answers, “I will not lend it to you, just as you refused to lend it to me,” that is vengeance. But if he answers, “yHere it is; I am not like you, who would not lend it to me,” that is bearing a grudge. For in a case where his friend owes him money, such as because of damage that he caused him or for similar reasons, one is not obliged to let his friend go free. On the contrary, he should sue him before the court and receive payment from him, on the basis of the verse which states, as he hath done, so shall it be done to him,⁹⁴Further, 24:19. and he [who caused the damage] is himself obliged to pay just as he must pay back that which he borrowed or robbed; and how much more so in matters of life, [the next of kin] should take vengeance and guard the grudge against the murderer, until the blood of his brother be redeemed by a court that will render judgment according to the laws of the Torah.