Who said "A man must know himself before he can improve himself."?

This quote is attributed to Mr. Darcy.

A man must know himself before he can improve himself. - Mr. Darcy

"A man must know himself before he can improve himself."

Mr. Darcy

"It is a truth universally acknowledged that a single man in possession of a good fortune must be in want of a wife."

"I could easily forgive his pride if he had not mortified mine."

"You have bewitched me, body and soul."

"I am not one of those gentlemen who can be supposed to please women."