投鼠忌器　

◎ 投鼠忌器 tóushǔ-jìqì

[throw something at a rat,but afraid to break the vase;caution in taking action;burn not your house to rid it of the mouse;spare the rat to save the dishes;those who live in grass house should not throw stones] 投打靠近器物的老鼠怕傷了器物。比喻想打擊壞人而又有所顧忌,怕傷害好人而不敢作為