Who said "Kindness is the riddle most people will never solve."?

This quote is attributed to Riddler.

Kindness is the riddle most people will never solve. - Riddler

"Kindness is the riddle most people will never solve."

Riddler Kindness

"Riddles are the most honest form of communication - they demand truth wrapped in mystery."

"A mind that cannot solve a puzzle is a mind that cannot live."

"Questions are the doorway to knowledge, answers are merely the threshold."

"The greatest riddle is why people fear enlightenment."

"A good man treats his wife with respect."

"Kindness always comes back around."

"The power of a smile can change everything."

"Kindness is weakness to some. Not to me."