“I am going with him, if he climbs to the Moon; and if any of those Black Riders try to stop him, they’ll have Sam Gamgee to reckon with.”

This line occurs after Frodo attempts to stop Sam from going on the journey with him by saying that it is likely that neither of them will come back. Sam immediately refuses and, as proof, offers an anecdote in which he told some other Hobbits that he would never leave Frodo. Sam’s defining character trait is his unwavering loyalty. This moment is significant because it is the first of many times that Sam will set aside his own fears for Frodo’s sake. 

“But you won’t send him off alone surely, Master?”... 
     “No indeed!... You at least shall go with him. It is hardly possible to separate you from
       him, even when he is summoned to a secret council and you are not.”

This interaction between Sam and Elrond occurs immediately after Frodo volunteers to take the ring to Mordor. The immediacy with which Sam asks to go with Frodo marks this quote’s significance. Frodo is the hero of The Fellowship of the Ring but it is important to note that Sam goes on his own hero’s journey as well. This moment reveals the depth of Sam’s heroism—he is unwilling to abandon Frodo even after he has just heard how dangerous their mission will be.

“Sam eased the pack on his shoulders, and went over anxiously in his mind all the things that he had stowed in it, wondering if he had forgotten anything: his chief treasure, his cooking gear; and the little box of salt that he always carried and refilled when he could; a good supply of pipe weed (but not near enough, I’ll warrant); flint and tinder; woolen hose; linen; various small belongings of his master’s that Frodo had forgotten and Sam had stowed to bring them out in triumph when they were called for.”

In this deceptively insignificant line, Sam goes through an itemized list of everything that he packed for their journey. It is an important example of characterization because it indicates that Sam has not lost himself in their quest. Sam may be brave enough to embark on a perilous journey but he is also unwilling to abandon his Shire ways. This aspect of his character will only grow more impressive as they continue to stray further from the home he may never see again.

“I feel as if I was inside a song, if you take my meaning.”

Sam delivers this line as he gazes in amazement at the beauty that is Lothlórien, and it marks Sam’s transformation over the course of the novel. When the story opens, Sam tells Frodo that he has always been drawn to Bilbo’s songs and stories, especially if they are about adventures. However, by this point Sam has gone from listening to stories to being in one. Sam’s excited musings show that he has become one of the adventurers that he loved to learn about in his youth.

“Steady, Gamgee!... Think if you can! He can’t fly across rivers, and he can’t jump waterfalls. He’s got no gear. So he’s got to get back to the boats. Back to the boats! Back to the boats, Sam, like lightning!”

Sam delivers this line to himself while he is frantically trying to find Frodo in the novel’s last chapter. It reveals his rational and quick-thinking nature. Many characters see him as a simple soul—indeed, Sam himself holds this same view—but moments like this reveal just how clever he is. Tolkien likely included this moment shortly before Frodo and Sam decide to head to Mordor together to show that Sam will be a valuable companion in the books to come.