לא אלה. כְּתַרְגּוּמוֹ "דְּלֵית בְּהוֹן צְרוֹךְ", אִלּוּ הָיָה בָהֶם צְרוֹךְ לֹא הָיְתָה קִנְאָה כְפוּלָה כְּמוֹ עַכְשָׁו (ספרי): לא אלה — Understand this as the Targum does: They sacrifice unto devils in which is no utility, for if there were at least any utility in them to the world (as e.g:, the sun, moon and stars) God’s jealousy would not have been so intense (lit. — doubled) as it is now. (Sifrei Devarim 318:13).
חדשים מקרב באו. אֲפִלּוּ הָאֻמּוֹת לֹא הָיוּ רְגִילִים בָּהֶם — גּוֹי שֶׁהָיָה רוֹאֶה אוֹתָם, הָיָה אוֹמֵר זֶה צֶלֶם יְהוּדִי: חדשים מקרב באו [THEY SACRIFICED … TO GODS] THAT CAME UP REGENTLY — i.e. with which even the heathen nations were not familiar. Indeed, if a heathen saw them he would say, “This is a Jewish idol” (Sifrei Devarim 318:14).
לא שערום אבתיכם. לֹא יָרְאוּ מֵהֶם — לֹא עָמְדָה שַׂעֲרָתָם מִפְּנֵיהֶם, דֶּרֶךְ שַׂעֲרוֹת הָאָדָם לַעֲמֹד מֵחֲמַת יִרְאָה, כָּךְ נִדְרַשׁ בְּסִפְרֵי. וְיֵשׁ לְפָרֵשׁ עוֹד שערום לְשׁוֹן (ישעיה יג, כא) "וּשְׂעִירִים יְרַקְּדוּ שָׁם", שְׂעִירִים הֵם שֵׁדִים, לֹא עָשׂוּ אֲבוֹתֵיכֶם שְׂעִירִים הַלָּלוּ: לא שערום אבתיכם — This means, which your fathers feared not; more literally it means: Their hair (שער) did not stand up on end because of them — for it is the nature of a person’s hair to stand up out of fear. Thus is it (the word שערום) explained in Sifrei Devarim 318:15. But it is also possible to explain it as being connected with the noun in (Isaiah 13:21) “And שעירים shall dance there”; שעירים are demons (satyrs), and the meaning of our verse would then be: your fathers never made these satyrs.