Full Idea
Death is a separation of soul from body. But nothing incorporeal can be separated from a body. For neither does anything incorporeal touch a body, and the soul touches and is separated from the body. Therefore the soul is not incorporeal.
Gist of Idea
Death can't separate soul from body, because incorporeal soul can't unite with body
Source
Chrysippus (fragments/reports [c.240 BCE]), quoted by Tertullian - The Soul as an 'Astral Body' 5.3
Book Reference
'The Stoics Reader', ed/tr. Inwood,B/Gerson,L.P. [Hackett 2008], p.98
A Reaction
This is the classic interaction difficulty for substance dualist theories of mind.