The fool who knows his foolishness, is wise at least so far. But a fool who thinks himself wise, he is called a fool indeed.
Yo bālo maññati bālyaṁ, paṇḍito vāpi tena so; Bālo ca paṇḍitamānī, sa ve “bālo”ti vuccati.
Dhammapada 63
The same idea in other traditions
When pride cometh, then cometh shame; But with the lowly is wisdom.
Pride goeth before destruction, and an haughty spirit before a fall.
The Master said, "Learning without thought is labour lost; thought without learning is perilous."
Nor walk on the earth with insolence: for thou canst not rend the earth asunder, nor reach the mountains in height.
By humility he will acquire freedom from self-conceit; thereby he will become of a kind and meek disposition, and avoid the eight kinds of pride.
If I made a donation of castles of gold, and gave lots of fine horses and wondrous elephants in charity, and if I made donations of land and cows-even then, pride and ego would still be within me.
Little is known by any one but the spiritual man, / Who has in his heart a touchstone of vital truth. / The others, hovering between two opinions, / Fly towards their nest on a single wing. / Knowledge has two wings, opinion only one wing; / Opinion is weak and lopsided in its flight. …