Who said "Kindness is the first sign of weakness."?

This quote is attributed to Nelson Muntz.

Kindness is the first sign of weakness. - Nelson Muntz

"Kindness is the first sign of weakness."

Nelson Muntz Kindness

"Ha-ha!"

"Your tears of unfathomable sadness!"

"I'm gonna enjoy this, Bart. I'm gonna enjoy this a lot."

"Eat my shorts, Simpson!"

"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."