Heraclitus somewhere says that all things are in process and nothing stays still, and likening existing things to the stream of a river he says that you would not step twice into the same river.

Wisdom consists in speaking and acting the truth.

What sense or thought do they have? They follow the popular singers, and they take the crowd as their teacher.

The people must fight for their laws as for their walls.

Everything flows and nothing abides; everything gives way and nothing stays fixed... Cool things become warm, the warm grows cool; the moist dries, the parched becomes moist... It is in changing that things find repose.

All things come into being by conflict of opposites.

The sun is new each day.