A proverb meaning that someone else's misfortune could happen to you tomorrow; misfortune can befall anyone.
ニュースで災害の被害を見て、明日は我が身だと感じた。
Seeing the disaster damage on the news made me feel that it could happen to me too.
人の失敗を笑ってはいけない。明日は我が身だ。
You shouldn't laugh at someone else's mistake. It could be you next.
職場の整理で同僚が解雇された。明日は我が身だと皆心配している。
A colleague was dismissed in the company's reorganization. Everyone worries it could be them next.