As opposed to 湯から出た錆?

身から出た錆
(Mi kara deta sabi; “Tarnished from within.”)

Definition:

Suffering due to one’s own misdeeds, especially the bad things one has done to others. Paying for one’s mistakes; getting one’s just deserts. The image here is of rust developing from the iron content of a sword blade – a 刀身 (toushin).

Breakdown:

This noun phrase is built on 錆 (sabi), “rust” or “tarnish.” The rust 出た (deta) “came out,” past tense of 出る (deru). It came out から (kara), “from,” the 身 (mi), “body.”

Notes:

This appears in the Edo iroha karuta set, but is originally attributed to our old friend Kefukigusa (毛吹草).

Changing the verb to 出した (dashita), “put forth,” is less common but acceptable. Presumably it’s also possible to see alternate forms of 錆, such as the one with the 円 element written as 月.

Unlike the contemporary GOP, Japanese culture is full of this sort of admonition that bad behavior leads to consequences that the responsible individual will face and suffer from – cf. 自業自得 and 自縄自縛.

Example sentence:

「まさ君にフラれたの？それは身から出た錆よ、小学校の時ずっと苛めてたし」

(“Masa-kun ni furareta no? Sore wa mi kara deta sabi yo, shougakkou no toki zuutto ijimeteta shi.”)

[“Masa rejected you? You reap what you sow, and you bullied him all the time in elementary school.”]