not lift a finger

not lift a finger (to help someone)

 and not lift a hand (to help someone)
Fig. to do nothing to help someone. (The someone is anyone with the negative.) They wouldn't lift a finger to help us. Can you imagine that they wouldn't lift a finger? Sally refused to lift a hand to help her own sister.
See also: finger, lift, not

not lift a finger

to refuse to make even a small effort He spends all day stretched out on the couch and doesn't lift a finger to help.
See also: finger, lift, not

not lift a finger

Refuse to exert oneself to help or perform an action. For example, Dad won't lift a finger to help them financially, or Early in the war, America officially would not lift a finger. [Mid-1900s]
See also: finger, lift, not
References in classic literature ?
I should consider myself bound in honor not to help you--but I would not lift a finger to prevent you from discovering the truth for yourself.