"There was once a little man called Niggle, who had a long journey to make. He did not want to go, indeed the whole idea was distasteful to him; but he could not get out of it. He knew he would have to start some time, but he did not hurry with his preparations."
This quote, the opening lines of the story, is the reader's first introduction to Niggle. This description is a rather general one, and it makes him appear as a sort of everyman; as becomes clear through the course of the story, this "journey" is death, the long journey to the afterlife. Most people know they will have to go eventually, but they view death as a distasteful problem for another day, living in the moment instead of making preparations. Just like Niggle, however, they often find themselves unprepared just before the journey begins.
"'What was the matter with him?' said a Second Voice, a voice that you might have called gentle, though it was not soft - it was a voice of authority, and sounded at once hopeful and sad."
When Niggle hears the Second Voice, he finds it gentler and kinder than the First Voice. Indeed, the Second Voice is the one who defends Niggle for his work on earth, and convinces the First Voice to allow Niggle to move on to the next stage. In the allegory of the Christian afterlife, the Second Voice is often compared to Jesus Christ – the merciful son of God who was both fully human and fully divine.
"Things might have been different, but they could not have been better."
This particular quote from Niggle is spoken to Parish after the two of them have completed their transformation of the fairy-tale landscape, using Niggle's artistic skill and Parish's gardening proficiency. Looking back on their lives and interactions, Niggle notes that things could have been different, but they could not have been better, meaning that life is beautiful, and everything that happens does so for a reason, perhaps even one invisible to those involved at the time. Niggle's reflection helps emphasize the hopeful and optimistic tone of the story.
"Even little Niggle in his old home could glimpse the Mountains far away, and they got into the borders of his picture; but what they are really like, and what lies beyond them, only those can say who have climbed them."
In "Leaf by Niggle," the Mountains represent Heaven, the land beyond all imagination and the final destination of the properly ordered human soul. At the end of the story, Niggle completes his work in the fairy-land and enters the land of the Mountains, where it is implied that he and Parish live forever in eternal joy. These Mountains, Tolkien says, can be glimpsed from the old life, and bits and pieces can be hinted at through art and other forms of beauty, but true knowledge of the Mountains can only be obtained by entering them oneself, paralleling the overwhelming goodness and beauty of Heaven.
"I can't get it out of my mind."
When the townspeople are speaking about Niggle, Atkins notes that he found a piece of Niggle's old canvas with the painting of a leaf on it. Here, despite the mocking nature of the conversation, Atkins admits that Niggle's work still stuck with him. The story therefore suggests that, though Niggle's reputation is largely nonexistent on earth, his creativity did affect one person, however briefly.
"They both laughed. Laughed - the Mountains rang with it!"
At the end of the story, the two Voices are discussing Niggle's Parish, the new name for the land that Niggle and Parish helped cultivate before moving onto the Mountains. The Second Voice notes that it sent a message to Niggle and Parish notifying them of the new name, and their response was laughter. Here, in the final line of the story, the Second Voice implies that both Niggle and Parish are living blissfully in the Beyond.
