Who said "Every dog has his day, but every friend has his purpose."?

This quote is attributed to Slinky Dog.

Every dog has his day, but every friend has his purpose. - Slinky Dog

"Every dog has his day, but every friend has his purpose."

Slinky Dog

"A dog's loyalty knows no bounds, partner. That's what friendship is all about."

"When life gets rough, you gotta stay springy and bounce back."

"There's nothing better than being there for someone when they need you most."

"A good friend sticks by you through thick and thin, no matter what."