Full Idea
Every movement being either a push or a pull, there must be a still point as with the circle, and this will be the point of departure for the movement.
Gist of Idea
If all movement is either pushing or pulling, there must be a still point in between where it all starts
Source
Aristotle (De Anima [c.329 BCE], 433b26)
Book Reference
Aristotle: 'De Anima (On the Soul)', ed/tr. Lawson-Tancred,H.C. [Penguin 1986], p.216