At the opening of his words/ in his introduction/ prologue
In the beginning of the things, he said them.
(At the beginning of the words he said them. ("The opening of your words enlightens the understanding of the simple" - Psalms 119:130, and likewise: "And behold what Maimonides wrote... and behold also that at the opening of his words he wrote as we explained, that one who defiles the outer house" - Shulchan Aruch, Yoreh De'ah, Laws of Niddah, last booklet, section 175, and also: "Rabba bar Bar Hana said etc., and this is also hinted at in the opening of his words" - Rabbi Nachman of Breslov, Likutei Moharan, Torah 7)
Translation
Expression (Hebrew)
בְּפֶתַח דְּבָרָיו
Definition (Hebrew)
בִּתְחִלַּת הַדְּבָרִים אוֹתָם אָמַר.
("פֵּתַח דְּבָרֶיךָ יָאִיר מֵבִין פְּתָיִים"- תְּהִלִּים קַיִט קַל, וְכֵן: "וְהִנֵּה מָה שֶׁכָּתַב הָרַמְבָּ"ם ...וְהִנֵּה גַּם בְּפֶתַח דְּבָרָיו כָּתַב כְּמוֹ שֶׁבֵּאַרְנוּ, דְּהַיְנוּ שֶׁמְּטַמֵּא בַּבַּיִת הַחִיצוֹן"- שֻׁלְחָן עָרוּךְ , יוֹרֶה דֵּעָה הִלְכוֹת נִדָּה קוּנְטְרֵס אַחֲרוֹן סִימָן קפג, וְכֵן: "אָמַר רַבָּה בַּר בַּר חָנָה וְכוּ', וְזֶה רֶמֶז גַּם כֵּן בְּפֶתַח דְּבָרָיו"- ר' נַחְמָן מִבְּרֶסְלָב/ לִקּוּטֵי מוהר"ן, תּוֹרָה ז')