expression, noun, noun which may take the genitive case particle 'no'
godsend; lifesaver; timely help; windfall
Idiomatic expression meaning a piece of good luck or a helpful coincidence that arrives just when needed, like a boat appearing when you need to cross a river.
彼が手伝ってくれるなんて、渡りに船だ。
It's a godsend that he's going to help me.
この求人はまさに渡りに船だった。
This job offer was truly a timely piece of luck.
Both mean unexpected good fortune, but 渡りに船 emphasizes timely help that solves a problem, while 棚からぼた餅 is more about receiving a windfall without effort.
Both describe a savior in a difficult situation, but 渡りに船 is a broader metaphor for any timely assistance, whereas 地獄で仏 specifically implies a kind person appearing in a harsh environment.
Literally 'a boat at the crossing'. The phrase originates from the idea that when you need to cross a river, a boat conveniently appears, symbolizing a timely and fortunate coincidence.