(א) על פני תרח אביו. בְּחַיֵי אָבִיו. וּמִדְרַשׁ אַגָּדָה אוֹמֵר שֶׁעַל יְדֵי אָבִיו מֵת; שֶׁקָּבַל תֶּרַח עַל אַבְרָם בְּנוֹ לִפְנֵי נִמְרוֹד עַל שֶׁכִּתֵּת אֶת צְלָמָיו, וְהִשְׁלִיכוֹ לְכִבְשַׁן הָאֵשׁ, וְהָרָן יוֹשֵׁב וְאוֹמֵר בְּלִבּוֹ אִם אַבְרָם נוֹצֵחַ אֲנִי מִשֶּׁלּוֹ, וְאִם נִמְרוֹד נוֹצֵחַ אֲנִי מִשֶּׁלּוֹ; וּכְשֶׁנִּצַּל אַבְרָם, אָמְרוּ לוֹ לְהָרָן מִשֶּׁל מִי אַתָּה? אָמַר לָהֶם הָרָן מִשֶּׁל אַבְרָם אֲנִי, הִשְׁלִיכוּהוּ לְכִבְשַׁן הָאֵשׁ וְנִשְׂרַף, וְזֶהוּ אוּר כַּשְׂדִים (ב"ר). וּמְנַחֵם פֵּרֵשׁ אוּר – בִּקְעָה; וְכֵן בָּאֻרִים כַּבְּדוּ ה' (ישעיה כ"ד), וְכֵן מְאוּרַת צִפְעוֹנִי (שם י"א) כָּל חֹר וּבֶקַע עָמֹק קָרוּי אוּר:
(1) על פני תרח אביו IN THE PRESENCE OF HIS FATHER TERAH — meaning during his father’s lifetime (Genesis Rabbah 38:13). The Midrashic explanation is that he died through his father. For Terah accused his son Abram before Nimrod of haying smashed his idols to pieces, and he cast him into a fiery furnace. Haran waited and said to himself, “If Abram proves triumphant I will be on his side; if Nimrod wins I shall be on his”. When Abram was saved they said to Haran, “Whose side are you on?” Haran replied, “I am on Abram’s side”. They therefore cast him into the fiery furnace and he was burnt to death. It is to this that the name of the place Ur-Kasdim (fire of the Chaldees) alludes (Genesis Rabbah 38:13). Menachem ben Seruk, however, explains that אור means a valley, as (Isaiah 24:15) “Glorify ye the Lord in the valleys (באורים)”, and as (Isaiah 11:8) “the den (מאורת) of the basilisk”. Every hole or deep cleft may be called אור.