Who said "Kindness costs nothing but returns everything."?

This quote is attributed to Courage the Cowardly Dog.

Kindness costs nothing but returns everything. - Courage the Cowardly Dog

"Kindness costs nothing but returns everything."

Courage the Cowardly Dog Kindness

"Courage, the cowardly dog."

"What's wrong, Muriel?"

"Oh, the things I do for love."

"Stupid Eustace!"

"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."