a friend in need is a friend indeed 患难见真情；患难之交才是真朋友

【例句】
I'll always be grateful to Tom for helping1 me; a friend in need is a friend indeed!
我将永远感激汤姆对我的帮助，患难见真情！

He stayed with me throughout the timeI was in the hospital, a friend in need is a friend indeed!
我住院期间他一直陪着我，患难中的朋友才是真正的朋友！