It is one of the traits of the soul (that can be acquired - Rabbi Hyamson). When it becomes established in the soul, its signs will appear in the limbs. Among them: a soft tongue, a low voice, humility at a time of anger, little exacting revenge when one has the power to do so. It as was said about a certain king who told a man who was convicted and a whip had already been brought [for punishment]: "I swear by G-d, if I did not feel such a strong anger against you, I would have exacted a severe revenge on you." Then he pardoned him. It is said of him that he would say: "I don't know of any sin of others which are greater than mine".
אֲבָל הַכְּנִיעָה הִיא שִׁפְלוּת הַנֶּפֶשׁ וְשַׁחוּתָהּ וּמִעוּט עֶרְכָּהּ אֶצְלָהּ.
What is submission
Submission is lowliness of the soul, its bowing down and not thinking much of itself.
וְהִיא מִדָּה מִמִּדּוֹת הַנֶּפֶשׁ וְכַאֲשֶׁר תִּתְיַשֵּׁב בָּהּ יֵרָאוּ אוֹתוֹתֶיהָ עַל הָאֵבָרִים, מֵהֶם הַלָּשׁוֹן הָרַכָּה וְהַקּוֹל הַנָּמוּךְ וְהָעֲנָוָה בְּעֵת הַכַּעַס וּמִעוּט הַנְּקָמָה אַחַר הַיְּכֹלֶת עָלֶיהָ כַּאֲשֶׁר נֶאֱמַר עַל אֶחָד הַמְּלָכִים שֶׁאָמַר לְמִי שֶׁנִּתְחַיֵּב אֶצְלוֹ לְאַחַר שֶׁהֵבִיאוּ הַשּׁוֹט חַי ה׳ לוּלֵא חֶזְקַת כַּעְסִי עָלֶיךָ הָיִיתִי נוֹקֵם מִמְּךָ נְקָמָה גְּדוֹלָה וּמָחַל לוֹ וְאָמְרוּ עָלָיו שֶׁהָיָה אוֹמֵר אֵינִי יוֹדֵעַ עָוֹן שֶׁהוּא שׁוֹקֵל יוֹתֵר מֵעֲוֹנֹתַי (ס״א מֵעַנְוָתִי.).
It is one of the traits of the soul (that can be acquired - Rabbi Hyamson). When it becomes established in the soul, its signs will appear in the limbs. Among them: a soft tongue, a low voice, humility at a time of anger, little exacting revenge when one has the power to do so. It as was said about a certain king who told a man who was convicted and a whip had already been brought [for punishment]: "I swear by G-d, if I did not feel such a strong anger against you, I would have exacted a severe revenge on you." Then he pardoned him. It is said of him that he would say: "I don't know of any sin of others which are greater than mine".