まさかのとき
masakano toki

Expression

1. in time of need; for a rainy day; in case of emergency

まさかのときともこそしんとも
masakano tokino tomokoso shinno tomo.
A friend in need is a friend indeed.
まさかのときにそなえて貯蓄ちょちくせよ。
masakano tokini sonaete chochiku seyo.
Keep something for a rainy day.