expression
turning to God only in one's trouble; praying only when in need
Proverbial expression criticizing those who seek divine help only when facing difficulties, ignoring faith in good times. Often used to describe opportunistic or last-resort reliance on religion.
普段は信心深くないのに、試験前だけ神社に行くなんて、まさに叶わぬ時の神頼みだ。
Going to a shrine only before exams, when you're not usually devout, is a perfect example of turning to God only in your trouble.
彼は困ったときだけ祈る、叶わぬ時の神頼みの典型だ。
He only prays when he's in trouble—a classic case of turning to God only in one's trouble.
Synonymous expression with the same meaning; 叶わぬ時 emphasizes unfulfilled wishes, while 苦しい時 emphasizes hardship.
A fixed idiomatic expression combining 叶わぬ (negative form of 叶う, 'to come true') + 時 ('time') + 神頼み ('prayer to gods'). The exact origin is uncertain, but it reflects a common proverbial criticism of opportunistic faith.