תֶּחְשַׁ֣כְנָה עֵ֭ינֵיהֶם מֵרְא֑וֹת וּ֝מָתְנֵ֗יהֶם תָּמִ֥יד הַמְעַֽד׃
Que leurs yeux s’assombrissent, perdent la vue! Fais vaciller sans cesse leurs reins.
Rashi
מחץ מתנים קמיו means, smite those who rise up against him with a smiting of the loins, similar to the idea that is expressed, (Psalms 69:24) “Make their loins continually to totter”. It was about those who contested the High priesthood that he spake thus. — Another explanation: He foresaw that Hasmon and his sons would in future war with the Greeks, and he therefore prayed for them, because they were few in number, viz., the twelve sons of Hasmon and Eleazar against several myriads of the enemy. On this account he prayed ברך ה׳ חילו ופעל ידיו תרצה BLESS, O LORD, HIS ARMY AND ACCEPT FAVOURABLY THE WORK OF HIS HANDS (cf. Genesis Rabbah 99:2; Midrash Tanchuma, Vayechi 14).