A person does not envy his son or his student
A person does not usually feel envy toward his son or his student, as both are the fruits of his nurturing and part of his personal achievements.
("From here you learn that a person does not envy his son, nor his student" – Midrash Zuta, Ecclesiastes (Buber), section 7. Also: "Even though a person does not envy his student, it is a great wisdom when the student consults his teacher and seeks his advice, giving him satisfaction, showing that he still needs him" – Agnon, Ir uMelo'ah, p. 95)
Translation
Expression (Hebrew)
אֵין אָדָם מִתְקַנֵּא בִּבְנוֹ וּבְתַלְמִידוֹ
Definition (Hebrew)
אָדָם אֵינוֹ נוֹהֵג לָחוּשׁ תְּחוּשַׁת קִנְאָה כְּלַפֵּי בְּנוֹ אוֹ כְּלַפֵּי תַּלְמִידוֹ שֶׁשְּׁנֵיהֶם הִנָּם פְּרִי טִפּוּחָיו וְחֵלֶק מֵהֶשֵּׂגָיו הָאִישִׁיִּים.
("מִכָּאן אַתָּה לָמַד שֶׁאֵין אָדָם מִתְקַנֵּא לֹא עַל בְּנוֹ, וְלֹא עַל תַּלְמִידוֹ"-מִדְרַשׁ זוּטָא, קֹהֶלֶת (בּוּבֶּר) פָּרָשָׁה ז, וְכֵן:"שֶׁאֲפִלּוּ אֵין אָדָם מִתְקַנֵּא בְּתַלְמִידוֹ חָכְמָה גְּדוֹלָה הִיא כְּשֶׁהַתַּלְמִיד נִמְלַךְ בְּרַבּוֹ וְשׁוֹאֵל בַּעֲצָתוֹ,עוֹשֶׂה לוֹ נַחַת רוּחַ, שֶׁמַּרְאֶה לוֹ שֶׁעֲדַיִן צָרִיךְ לוֹ"-עַגְנוֹן/ עִיר וּמְלוֹאָהּ, 95)