Chapter 19-What do you think Tolkien is saying about Bilbo's "luck" in the following passage from the end of the story?

Gandalf says to Bilbo, "You don't really suppose, do you, that all your adventures and escapes were managed by mere luck, just for your sold benefit? You are a vdry fin per-son, Mr. Baggins, and I am very fond of you; but you are only quite a little fellow in a wide world after all"