Full Idea
Zeno held (contrary to Xenocrates and others) that it was impossible for anything to be effected that lacked a body, and indeed that whatever effected something or was affected by something must be body.
Gist of Idea
A body is required for anything to have causal relations
Source
report of Zeno (Citium) (fragments/reports [c.294 BCE]) by M. Tullius Cicero - Academica I.39
Book Reference
'The Stoics Reader', ed/tr. Inwood,B/Gerson,L.P. [Hackett 2008], p.86
A Reaction
This seems to make stoics thoroughgoing physicalists, although they consider the mind to be made of refined fire, rather than of flesh.