אָמַ֗רְתָּ הִנֵּ֤ה הִכִּ֙יתָ֙ אֶת־אֱד֔וֹם וּנְשָׂאֲךָ֥ לִבְּךָ֖ לְהַכְבִּ֑יד עַתָּה֙ שְׁבָ֣ה בְּבֵיתֶ֔ךָ לָ֤מָּה תִתְגָּרֶה֙ בְּרָעָ֔ה וְנָ֣פַלְתָּ֔ אַתָּ֖ה וִיהוּדָ֥ה עִמָּֽךְ׃
Thou sayest—lo, thou hast smitten Edom; will thy heart therefore lift thee up to glory therein? abide now at home; why shouldest thou meddle with evil, that thou shouldest fall, even thou, and Judah with thee?’
Rashi
from the fear of Your hand Heb. מתגרת, from the fear of Your blows. תגרת is an expression of (Num. 22:3): “And Moab became terrified (וַיָגָר).” The “tav” is a defective radical in the word, like תנובה, produce; תלונה, complaint; תקומה, restoration; תכונה, characteristic. This is how Menachem explained it, but I maintain that תגרת is not an expression of מָגוֹר, fear, because he should have said תגוּרה as he says from: וישב (and he returned) תשוּבה, [from] ויקם, וירם and וילן: תקוּמה, תרוּמה and תלוּנה, so he should say from ויגר, תגוּלה, or מגוּרה as (above 31:14, Jer. 20:3): “terror (מגור) from all sides”; (Isa. 66:4) “and their fears (ומגורתם) I will bring.” Thus you learn that מתגרת is nothing but as (II Chron. 25:19), “Why should you provoke (תתגרה) disaster?”; (Deut. 2:5), “Do not provoke (תתגרו) them,” in which case the verb is גרה like קוה, to hope; אוה, to desire; צוה, to command, of which the noun is תקוה, תאוה, מצוה. So one says from גרה, תגרה, and this is its explanation: from the blows of Your hand, with which You fight me, I perish.