You shall be holy. As I heard that in the parasha Kedoshim it opens with "you shall be holy" [also an explanation that it is a reassurance that they will be holy in everything that is written in the parsha] that is impossible for a person to do all the mitzvot written in the parsha if one is not holding oneself in holiness in what is written beforehand. And he said, as example, that "love your neighbor as yourself" is impossible to do, what can one do if in one's heart one hates the fellow nonetheless, or maybe just does not love the fellow, and all the exertions of one's heart will definitely not help if beforehand one has not reached the level of holiness.
קְדֹשִׁים תִּהְיוּ. כְּמוֹ שֶׁשָּׁמַעְתִּי דִּבְפָרָשַׁת קְדֹשִׁים הַפְּתִיחָה "קְדֹשִׁים תִּהְיוּ" [וּפֵירוּשׁ גַּם כֵּן שֶׁהוּא הַבְטָחָה שֶׁאָז יִהְיוּ קְדוֹשִׁים כָּל הַכָּתוּב בַּפָּרָשָׁה] שֶׁאִי אֶפְשָׁר לְאָדָם לְקַיֵּים הַמִּצְוֹת הַכְּתוּבוֹת בְּפָרָשָׁה זוֹ אִם לֹא כַּאֲשֶׁר יִהְיֶה קָדוֹשׁ בְּכָל הַכָּתוּב קוֹדֶם. וְאָמַר לְמָשָׁל מִצְוַת "וְאָהַבְתָּ לְרֵעֲךָ" שֶׁאֵין בְּיַד הָאָדָם כְּלָל לְקַיְּמוֹ, דְּמַה יַּעֲשֶׂה וְלִבּוֹ מִכָּל מָקוֹם שׂוֹנְאוֹ אוֹ אֵינוֹ אוֹהֲבוֹ וְכָל הִשְׁתַּדְּלוּת הַלֵּב שֶׁיֹּאהֲבֶנּוּ כָּמוֹהוּ מַמָּשׁ לֹא יוֹעִילוֹ אִם לֹא קָדַם לְהַגִּיעַ לְמַדְרֵגַת הַקְּדוּשָּׁה.
(דובר צדק כ"ז: ד"ה והנה ד"ז)
You shall be holy. As I heard that in the parasha Kedoshim it opens with "you shall be holy" [also an explanation that it is a reassurance that they will be holy in everything that is written in the parsha] that is impossible for a person to do all the mitzvot written in the parsha if one is not holding oneself in holiness in what is written beforehand. And he said, as example, that "love your neighbor as yourself" is impossible to do, what can one do if in one's heart one hates the fellow nonetheless, or maybe just does not love the fellow, and all the exertions of one's heart will definitely not help if beforehand one has not reached the level of holiness.