Question: who says all that is gold does not glitter?
Answer: All that is Gold Does Not Glitter was a poem written by Bilbo Baggins to describe Aragorn, used to help convince Frodo and company to trust him in his guise as "Strider". Gandalf includes the poem in his letter to Frodo, which he leaves at The Prancing Pony for Barliman Butterbur to deliver.