(source) 
Plato
(c. 427 B.C.  c. 347 B.C.)

“Yes,” he said. “But these things (the solutions to problems in solid geometry such as the duplication of the cube) do not seem to have been discovered yet.” “There are two reasons for this,” I said. “Because no city holds these things in honour, they are investigated in a feeble way, since they are difficult; and the investigators need an overseer, since they will not find the solutions without one. First, it is hard to get such an overseer, and second, even if one did, as things are now those who investigate these things would not obey him, because of their arrogance. If however a whole city, which did hold these things in honour, were to oversee them communally, the investigators would be obedient, and when these problems were investigated continually and with eagerness, their solutions would become apparent.”
— Plato
An astronomer must be the wisest of men; his mind must be duly disciplined in youth; especially is mathematical study necessary; both an acquaintance with the doctrine of number, and also with that other branch of mathematics, which, closely connected as it is with the science of the heavens, we very absurdly call geometry, the measurement of the earth.
— Plato
At the Egyptian city of Naucratis there was a famous old god whose name was Theuth; the bird which is called the Ibis was sacred to him, and he was the inventor of many arts, such as arithmetic and calculation and geometry and astronomy and draughts and dice, but his great discovery was the use of letters.
— Plato
Let noone ignorant of geometry enter.
— Plato
The ludicrous state of solid geometry made me pass over this branch.
— Plato
The science [geometry] is pursued for the sake of the knowledge of what eternally exists, and not of what comes for a moment into existence, and then perishes.
[Also seen condensed as: ``Geometry is knowledge of the eternally existent” or “The knowledge at which geometry aims is the knowledge of the eternal.”]
[Also seen condensed as: ``Geometry is knowledge of the eternally existent” or “The knowledge at which geometry aims is the knowledge of the eternal.”]
— Plato