Isaiah 51:13
וַתִּשְׁכַּח ה’ עֹשֶׂךָ נוֹטֶה שָׁמַיִם וְיֹסֵד אָרֶץ וַתְּפַחֵד תָּמִיד כָּל הַיּוֹם מִפְּנֵי חֲמַת הַמֵּצִיק כַּאֲשֶׁר כּוֹנֵן לְהַשְׁחִית וְאַיֵּה חֲמַת הַמֵּצִיק
You forgot Hashem your Maker, the One Who stretched forth the heavens and laid out the foundations of the earth; you fear continually all day long because of the fury of the oppressor, as he prepares to destroy - but where is the fury of the oppressor?
This verse is referenced in the prayer Aleinu. The Mahari Kara points out an interesting fact about these oppressors. They prepare to destroy but, ultimately, they are only planning their own destruction. He give the example of Haman, who cast lots to determine the auspicious day to destroy the Jewish. The Jews were terrified but it was Haman who ended up being destroyed by his own plot.