Sitting by a tree Stump, Waiting for a Careless hare

In the Spring and Autumn Period, a farmer in the State of Song was one day working in the fields when he saw a rabbit bump into a tree stump accidentally and break its neck. The farmer took the rabbit home, and cooked himself a delicious meal. That night he thought, 'I needn't work so hard. All I have to do is wait for a rabbit each day by the stump.' So from then on he gave up farming, and simply sat by the stump waiting for rabbits to come and run into it. 

春秋时代，宋国有个农夫，一天在耕田的时候，忽然跑来一只兔子，恰巧碰在树桩上，脖子折断死了。农夫把兔子拾回家去，美美地吃了一顿兔肉。晚上他想：“我何必辛辛苦苦地种地呢？每天在树下能捡到一只兔子就够我吃的了。”于是，他从此不再耕作，每天坐在树下等待兔子的到来。

This idiom satirizes those who just wait for a stroke of luck, rather than making efforts to obtain what they need.

“守株待兔”这个成语，讥笑那些不想经过努力，存在侥幸心理，希望得到意外收获的人。