Diogenes Laertius Vitae philosophorum 7.1.140

[140] The world, they say, is one and finite, having a spherical shape, such a shape being the most suitable for motion, as Posidonius says in the fifth book of his Physical Discourse and the disciples of Antipater in their works on the Cosmos. Outside of the world is diffused the infinite void, which is incorporeal. By incorporeal is meant that which, though capable of being occupied by body, is not so occupied. The world has no empty space within it, but forms one united whole. This is a necessary result of the sympathy and tension which binds together things in heaven and earth. Chrysippus discusses the void in his work On Void and in the first book of his Physical Sciences; so too Apollophanes in his Physics, Apollodorus, and Posidonius in his Physical Discourse, book ii. But these, it is added [ i.e. sympathy and tension], are likewise bodies. ¹