הַמַּשְׂבִּ֣יַע בַּטּ֣וֹב עֶדְיֵ֑ךְ תִּתְחַדֵּ֖שׁ כַּנֶּ֣שֶׁר נְעוּרָֽיְכִי׃
좋은 것으로 네 소원을 만족케 하사 네 청춘으로 독수리 같이 새롭게 하시는도다
Rashi
that your youth renews itself like the eagle Like this eagle, which renews its wings and feathers from year to year. There is a Midrash Aggadah about a kind of eagle that returns to its youth when it becomes old.