Full Idea
Where actions proceed not from some cause in the characters and dispositions of the person who performed them, they infix not themselves upon him, and can neither redound to his honour if good, nor infamy if evil. The action in itself may be blameable.
Gist of Idea
You can only hold people responsible for actions which arise out of their character
Source
David Hume (Treatise of Human Nature [1739], II.III.2), quoted by Philippa Foot - Free Will as Involving Determinism p.70
Book Reference
Foot,Philippa: 'Virtues and Vices' [Blackwell 1981], p.70
A Reaction
I agree with Foot that this is wrong. Uncharacteristic actions still reflect on the person. The last sentence is wrong too. If you ignore the agent of an action, it can't be distinguished from a flash of lightning.