Full Idea
According to Heracliteans, since things must be changing, and since lack of change can't be a property of anything, then everything is always undergoing change of every kind.
Gist of Idea
If flux is continuous, then lack of change can't be a property, so everything changes in every possible way
Source
comment on Heraclitus (fragments/reports [c.500 BCE], B030) by Plato - Theaetetus 182a
Book Reference
Plato: 'Theaetetus', ed/tr. Waterfield,Robin [Penguin 1987], p.82