扶危济困
Be a good Samaritan.
Help a lame dog over a stile.
eg：Be a good Samaritan and contribute much to the fund.
中英俚语俗语来源：水浒记传奇：“宋公明他扶危济困隐功曹。”
同义词：见义勇为 Do a good turn.
反义词：落井下石 When a dog is drowing, everyone offers him a drink.
