"Farewell!" they cried, "wherever you fare, till your eyries recieve you at the journey's end!" That is the polite thing to say among eagles.
"May the wind under your wings bear you where the sun sails & the moon walks", answered Gandalf, who knew the correct reply.
"So comes snow after fire, & even dragons have their ending!" said Bilbo, and he turned his back on his adventure [...] "I wish now only to be in my own armchair!" he said.