כֹּ֤ה אָמַר֙ יְהוָ֣ה צְבָא֔וֹת הִנְנִ֥י שֹׁבֵ֖ר אֶת־קֶ֣שֶׁת עֵילָ֑ם רֵאשִׁ֖ית גְּבוּרָתָֽם׃
Thus saith the LORD of hosts: Behold, I will break the bow of Elam The chief of their might.
Rashi on Jeremiah
the bow of Elam The might of Elam (other editions: the strength of Elam).