Who said "Ruh-roh! The night is dark, but friendship is light."?

This quote is attributed to Scooby-Doo.

Ruh-roh! The night is dark, but friendship is light. - Scooby-Doo

"Ruh-roh! The night is dark, but friendship is light."

Scooby-Doo Hope

"Scooby-Dooby-Doo, where are you?"

"Ruh-roh!"

"Like, zoinks!"

"Let's split up, gang!"

"Every day is a new opportunity."

"Hope is what gets us through difficult times."

"I'm not your enemy, kid. I'm trying to save you."

"Redemption is a long road."