Full Idea
Zeno held that an incorporeal substance was incapable of any activity, whereas anything capable of acting, or being acted upon in any way, could not be incorporeal.
Gist of Idea
Incorporeal substances can't do anything, and can't be acted upon either
Source
report of Zeno (Citium) (fragments/reports [c.294 BCE]) by M. Tullius Cicero - Academica I.11.39
A Reaction
This is substance dualism kicked into the long grass by Zeno, long before Descartes defended dualism, and was swiftly met with exactly the same response. The interaction problem.
Book Reference
Cicero: 'De Natura Deorum and Academica (XIX)', ed/tr. Rackham,H. [Harvard Loeb 1933], p.449