אל תשליכני לעת זקנה
“Do not cast us aside in old age”

QUESTION: “Le’eit ziknah” literally means “to old age.” Grammatically, shouldn’t we say “Al tashlicheinu be’eit ziknah”?

ANSWER: The Gemara (Ta’anit 5b) says that when Hashem found it necessary for the prophet Shmuel to expire, He made him age prematurely (to remove any implication that he had sinned). Thus, the intent of our prayer is that Hashem should let us fully enjoy the young and middle age portions of our life and that He should not, G‑d forbid, cast us prematurely into the period of “ziknah” — “old age” — the time of life when one is lacking in strength and vigor.

(לקוטי יהושע)