When Nick mentions this, he is referring to Gatsby's belief in the American Dream and his desire to achieve his goals and aspirations, represented by the green light at the end of Daisy's dock. The green light symbolizes hope and the promise of a better future, which Gatsby pursues relentlessly despite it always being just out of reach. It highlights the theme of longing and the impossibility of recapturing the past.
To stand for the lure of the American Dream that often proves elusive
by summing up the idea that motivated Gatsby, the author leaves the reader feeling beaten but determined to continue
Nick is primarily a static character in "The Great Gatsby" as he remains consistent in his moral values and role as a narrator throughout the novel. However, his views on Gatsby do evolve causing some to argue for a dynamic nature. One quote highlighting Nick's development is “Gatsby believed in the green light, the orgastic future that year by year recedes before us. It eluded us then, but that's no matter--tomorrow we will run faster, stretch out our arms farther... And then one fine morning-- So we beat on, boats against the current, borne back ceaselessly into the past.”
Situated at the end of Daisy's East Egg dock and barely visible from Gatsby's West Egg lawn, the green light represents Gatsby's hopes and dreams for the future. Gatsby associates it with Daisy, and in Chapter I he reaches toward it in the darkness as a guiding light to lead him to his goal. Because Gatsby's quest for Daisy is broadly associated with the American dream, the green light also symbolizes that more generalized ideal. In Chapter IX, Nick compares the green light to how America, rising out of the ocean, must have looked to early settlers of the new nation. "The green light on Daisy's house that Gatsby gazes wistfully at from his own house across the water represents the "unattainable dream." But the green light also represents the hazy future, the future that is forever elusive, as Nick claims in the last page of the novel, "Gatsby believed in the green light, the orgastic future that year by year recedes before us. It eluded us then, but that's no matter - to-morrow we will run farther, stretch out our arms farther...." The interesting question is, if the green light is the future, how is it so tied up with Daisy and the dreams of the past?"--Check out the included link for more info.
Gatsby's desire to regain what he once had
Gatsby's wild imaginings promised him a future where he would be reunited with his past love, Daisy, and they would live happily ever after. He believed achieving wealth and status would make him worthy of her love and bring her back to him.
The narrator, Nick Carraway, admires the innocence that Gatsby possesses. Although Gatsby gained his wealth through shady means, he only did so to obtain his goal of getting nearer to Daisy and reliving the past that they had together. Though Nick recognizes Gatsby's flaws the first time he meets him, he cannot help but admire Gatsby's brilliant smile, his romantic idealization of Daisy, and his yearning for the future.
Gatsby reaches out to the green light across the water, which symbolizes his dreams and hopes for the future. He associates the light with Daisy and the life he desires with her, symbolizing his longing for a better future and his pursuit of the American Dream.
Daisy broke her promise to wait for Gatsby and not marry Tom Buchanan. Despite telling Gatsby she would ultimately choose him, Daisy went through with her marriage to Tom, betraying Gatsby's trust and hopes for a future together.
The green lights symbolize the future he wishes to have, but only regarding Daisy. The lights were intended for Gatsby to see upon his return from the army but after Daisy is married and unaware of his return, they only shine the light of hope into Gatsby.
In my opinion, the green light has several meanings: 1) it is the symbol of hope that one day Daisy will see the green light and wonder who lives on the other side of the river and will discover the great mansion of Gatsby. 2) I think that Fitzgerald wanted a green light instead of a yellow or red light because a green light implies a moving forward and a future. Gatsby wanted nothing more then to let Daisy see that he was the right man all along and that now, when he is even more wealthy then Daisy, he is here future. Her green light.
He Believed in Himself and all the people around him or in the future.