expression
life is transient; life is uncertain; memento mori
A set phrase expressing the impermanence of life, often used in reflective or literary contexts. It conveys that one may be here today but gone tomorrow.
今日あって明日ない身だから、一日一日を大切に生きたい。
Since life is uncertain, I want to live each day with care.
expression
one's days are numbered; one's time is nigh
Used when someone's death is imminent or expected soon, often with a somber or fatalistic tone. More concrete than the general transience sense.
医者からはっきりとは言われなかったが、どうやら今日あって明日ない身らしい。
The doctor didn't say it outright, but it seems my days are numbered.
A classical Japanese idiom composed of 今日 (today), あって (exist), 明日 (tomorrow), ない (not exist), and 身 (body/self). The exact origin is uncertain, but it reflects a traditional awareness of life's fragility.