והתברך בלבבו. לְשׁוֹן בְּרָכָה, יַחֲשֹׁב בְּלִבּוֹ בִּרְכַּת שָׁלוֹם לְעַצְמוֹ לֵאמֹר, לֹא יְבוֹאוּנִי קְלָלוֹת הַלָּלוּ, אַך שלום יהיה לי: והתברך בלבבו AND HE BLESS HIMSELF IN HIS HEART — The word והתברך has the meaning of “blessing”. In his heart he will imagine for himself a blessing of peace, saying, “These curses will not come upon me, I shall have peace”.
והתברך. בנדי"רא שו"יא בְּלַעַז, כְּמוֹ וְהִתְגַּלָּח, וְהִתְפַּלֵּל: והתברך is benoir soi in old French, i.e. the verb is reflexive like והתגלח, “he shall shave himself”, והתפלל, he shall pray lit., he shall make himself the object of intercession.
בשררות לבי אלך. בְּמַרְאִית לִבִּי, כְּמוֹ (במדבר כ"ד) "אֲשׁוּרֶנּוּ וְלֹא קָרוֹב", כְּלוֹמַר, מַה שֶּׁלִּבִּי רוֹאֶה לַעֲשׂוֹת: בשררות לבי אלך means IN THE VIEWS OF MY HEART WILL I WALK, שררות being of a root which means to look, to see, as (Numbers 25:17): “I shall see him (אשרנו), but not now”; it is as much as to say, I will follow what my heart sees good to do.
למען ספות הרוה. לְפִי שֶׁאוֹסִיף לוֹ פֻּרְעָנוּת עַל מַה שֶּׁעָשָׂה עַד הֵנָּה בְשׁוֹגֵג, וְהָיִיתִי מַעֲבִיר עֲלֵיהֶם, וְגוֹרֵם עַתָּה שֶׁאֲצָרְפֵם עִם הַמֵּזִיד וְאֶפָּרַע מִמֶּנּוּ הַכֹּל, וְכֵן תִּרְגֵּם אֻנְקְלוֹס "בְּדִיל לְאוֹסָפָא לֵהּ חֶטְאֵי שָׁלוּתָא עַל זְדָנוּתָא" — שֶׁאוֹסִיף לוֹ אֲנִי הַשְּׁגָגוֹת עַל הַזְּדוֹנוֹת: למען ספות הרוה TO ADD DRUNKENNESS [TO THE THIRST] — In order that I may add punishment for him even for the sins he has committed until now inadvertently (for which the figurative expression in this sentence is הרוה, drunkenness: cf. the following passage in Rashi), and which I used to overlook; — but now he causes Me to combine them with those committed with premeditation and to exact punishment from him for everything. Onkelos, too, rendered it in a similar sense: “in order to add for him the sins of inadvertence to those of premeditation”, which can only mean. “In order that “I” may add sins of inadvertence to those of presumption”.
הרוה. שׁוֹגֵג, שֶׁהוּא עוֹשֶׂה כְאָדָם שִׁכּוֹר שֶׁהוּא עוֹשֶׂה שֶׁלֹּא מִדַּעַת: הרוה DRUNKENNESS figuratively describes the condition of a שוגג, one who acts inadvertently. The expression is an apt one because he acts like a drunken man who does things unwittingly,
הצמאה. שֶׁהוּא עוֹשֶׂה מִדַּעַת וּבְתַאֲוָה: הצמאה THE THIRST aptly describes the attitude of one who acts wittingly and out of desire.