Full Idea
If the mind has once been affected by two affects at once, then afterwards, when it is affected by one of them, it will also be affected by the other.
Gist of Idea
Once we have experienced two feelings together, one will always give rise to the other
Source
Baruch de Spinoza (The Ethics [1675], III Pr14)
Book Reference
Spinoza,Benedict de: 'Ethics', ed/tr. Curley,Edwin [Penguin 1996], p.78
A Reaction
This strikes me as better expressed than Hume's version, which relies on examples. It is more generalised than Hume, since it will cover contiguity and resemblance and causation, all under the heading of the arising affects.