Who said "To find happiness, you must first know yourself."?

This quote is attributed to Guardians of the Galaxy.

To find happiness, you must first know yourself. - Guardians of the Galaxy

"To find happiness, you must first know yourself."

Guardians of the Galaxy Happiness

"I'm your friend, man. I do this because you're my friend."

"Sometimes the thing you fight the most is the thing you need the most."

"We are Groot."

"You're welcome for saving the galaxy, by the way."

"Babalú!"

"My greatest joy is making people smile."

"Laughter and love make a home."

"The best things in life are free."