Friendship and loyalty were two of the qualities that made it possible for the Quest to be successful.  Without that “one for all” spirit, Frodo would never have been successful in taking the Ring to Mordor, and Sauron would have gotten it back and covered all of Middle-earth in a thick spiritual darkness. 

Samwise Gamgee was more than just Frodo’s gardener.  He was also his friend, and he was very loyal to Frodo; he never once considered abandoning him on the Quest, despite all of the danger that they went through.  On more than one occasion, he was faced with the decision of staying with Frodo and leaving him; each time, he chose to stay with his master.  For example, in the Shire, Sam told Frodo, “If you don’t come back, sir, then I shan’t, that’s certain…I know we are going to take a very long road, into darkness, into darkness; but I know I can’t turn back…I must see it through, sir, if you understand me.’”  In Lothlorien, after Sam had seen the destruction of the Shire and his gaffer’s eviction from his home in the Mirror of Galadriel, he said, “No, I’ll go home by the long road with Mr. Frodo, or not at all.’”  In Mordor, as Frodo and Sam were approaching Mount Doom, Sam had an argument with himself, which ended with his saying, “I’ll get there, if I leave everything but my bones behind…And I’ll carry Mr. Frodo up myself, if it breaks my back and heart.  So stop arguing!” 

Likewise, Frodo’s cousins, Merry and Pippin, were also very loyal to him.  Even before Frodo left Bag End, Merry, Pippin, and Sam got together and conspired to follow Frodo wherever he was going.  They made it clear to him that they were going to go with him or follow behind: as Merry told Frodo, “…you cannot trust us to let you face trouble alone, and go off without a word.  We are your friends, Frodo…We are horribly afraid—but we are going with you; or following you like hounds.” 

And go with him, they did, not only to Rivendell but also on the Quest to destroy the Ring.  Until the Fellowship of the Ring broke up at Parth Galen, all of the other hobbits stayed by his side; it helped Frodo enormously to know that his cousins and Sam were on the Quest with him.  Furthermore, Frodo was equally loyal to them.  It was his love for his friends that enabled him to resist the Barrow-wight, and to throw off the temptation to use the Ring to escape.  

And even when the Fellowship broke up, Sam did not leave Frodo.  When his master decided to leave the Fellowship because it was becoming clear that the ring had started to corrupt the others, Sam insisted on accompanying him.  After Frodo rescued Sam from a near-drowning on the River Anduin at Parth Galen, Sam told his employer, “I’m coming too, or neither of us isn’t going.  I’ll knock holes in all the boats first.”  From start to finish, he put Frodo’s needs above his own.  He boosted Frodo’s morale by encouraging him, by speaking of the Shire, and on more than one occasion, by making him laugh.  He rescued Frodo from the dungeon of Cirith Ungol.  In Mordor, he gave Frodo his own share of the food and water.  And he carried Frodo up the slopes of Mount Doom when the latter was too exhausted to keep on.  “Come, Mr. Frodo!...I can’t carry it for you, but I can carry you and it as well.  So up you get!  Come on, Mr. Frodo dear!  Sam will give you a ride.  Just tell him where to go, and he’ll go.”  Without Sam’s loyal support, Frodo never would have made it to the fires of Mount Doom.

Aragorn and Gandalf were friends, as well.  They had known each other for decades, ever since Aragorn had first met him five years after he had first left Rivendell and gone out into the Wild.  In addition to traveling by himself or with his fellow Rangers, Aragorn had also traveled with Gandalf.  It was Gandalf who told him about Frodo, and who trusted him to look after Frodo when he could not do so himself.  It was from Gandalf that Aragorn acquired the wisdom he needed not only to help lead the Fellowship on its Quest, but to take over after Gandalf’s fall in Moria.  Later, he drew on that wisdom to become a good King of Gondor and Arnor.

Gimli and Legolas were members of two races that were quite hostile towards each other.  One was a dwarf and the other was an elf.  Yet, despite their differences, during their time in Lothlorien, they overcame the hostility between their races and became friends and comrades.  And they remained friends for the rest of Gimli’s life.  During the Quest, they made an agreement to tour Fangorn and the Glittering Caves of Aglarond, an agreement that they kept when the Quest was over.  Together, they fought fiercely at the Battle of Helm’s Deep, and their shared loyalty to Aragorn led to their accompanying him on the Paths of the Dead.

Indeed, all of the members of the Fellowship became friends with one another,with a loyalty to match.  Boromir tried to rescue Merry and Pippin from the Uruk-hai when they were captured; afterward, Aragorn, Legolas, and Gimli darted across the plains of Rohan to rescue Merry and Pippin from their captors.

Gandalf not only discovered that Frodo’s ring was the One Ring, but it was he who sent the hobbit on what would end up becoming his Quest to destroy it.  When the Fellowship left Rivendell on that quest, Gandalf led the Fellowship and did his part to protect it from the dangers that it faced.  He fought the Wargs that attacked them following their failed attempt to travel over Caradhras.  “In the wavering firelight Gandalf seemed suddenly to grow: he rose up, a great menacing shape like the monument of some ancient king of stone set upon a hill.  Stooping like a cloud, he lifted a burning branch and strode to meet the wolves.  They gave back before him.  High in the air, he tossed the blazing brand.  It flared with a sudden white radiance like lightning; and his voice rolled like thunder.”  In Moria, Gandalf helped to fight the Orcs, and he single-handedly fought the Balrog, giving his life in the process.  Without Gandalf, Frodo would never have discovered the true identity of his magic ring until the Ringwraiths had overrun the Shire, and the Fellowship would have been hard-pressed to survive a number of the dangers that it ran into.

It was Gandalf who freed Theoden King from the corrupting influence of Wormtongue, and whose leadership abilities and intervention made it possible for Rohan, and then Gondor, to win three major battles.  And when the Quest was over, it was Gandalf who quite literally flew to the rescue of Frodo and Sam on the back of a great Eagle, accompanied by two other Eagles.

Aragorn, for his part, started exhibiting his own loyalty to his comrades early on, while he and the hobbits were still in Bree and even before.  He kept a lookout for them after he had learned from Gildor’s Elves that they had left the Shire, and when the hobbits parted company with Tom Bombadil on the Road four miles from Bree, he followed them there.  He pledged his fealty to Frodo: “I am Aragorn son of Arathorn, and if by life or death I can save you, I will.”  He protected them through the Ringwraiths’ nighttime attack on The Sign of the Prancing Pony.  He made the commitment to escort them to Rivendell, a commitment that he kept through toil, discomfort, and danger.  On Weathertop, Aragorn fought the Ringwraiths with flaming brands when they attacked the hobbits; after Frodo had been stabbed by the Witch-King of Angmar, he rendered first aid to Frodo and hurried the hobbits to Rivendell.  And then Aragorn accompanied the Fellowship on its Quest.  Later, he saved Merry’s life in Minas Tirith, and then, following the destruction of the Ring, the lives of Frodo and Sam (“…you went to the very brink of death ere he recalled you, putting forth all his power, and sent you into the sweet forgetfulness of sleep”).  He also tended Pippin’s injuries after he had been squashed by a troll during the final battle.  Without Aragorn, the hobbits would have never made it to Rivendell, and Frodo would have become a wraith under Sauron’s power.  Furthermore, without his skill as a healer, none of the hobbits would have survived the Quest.

It was the friendships formed by the Fellowship of the Ring and their loyalty to one another which, in large part, made it possible for the Fellowship to successfully complete the Quest.  It is clear that J.R.R. Tolkien put a great store on the importance of friendship and loyalty, because he made it such an important part of the novel.