Although what the reader learns of the neighbor is filtered through the speaker’s perspective, he emerges as a distinctive character. The neighbor seems to be an active but traditional man. He grasps stones firmly, and his opinion of the wall’s purpose is based in “his father’s saying.” The speaker emphasizes this connection with the past by having the neighbor repeat what seems to him a fact rather than an opinion.

In "Mending Wall" by Robert Frost, we hear two different voices, that of the speaker and that of his neighbor, and they have very different ideas about the wall between them.

The speaker is a fanciful fellow, and he says that "something there is that doesn't love a wall." He and his neighbor are always fixing the wall that stands between their properties. The speaker can understand the damage that hunters make to it, but there are gaps each spring that seem to have no explanation. He would like to say "elves," but he doesn't think that his neighbor would buy that.

The speaker, in fact, cannot understand why they have to keep a wall between their properties in the first place. The neighbor has only pine and the speaker apple trees, and neither of them are crossing the boundary line. There are no cows involved. So why do they need the wall? The speaker cannot grasp what he is walling in or walling out.

Yet the neighbor, the poem's second voice, insists that "good fences made good neighbors." This is a saying he has heard from his father, and he maintains it steadily in a show of good sense even though there is no practical reason for the wall. The neighbor has always had a wall, and that is good enough for him. He does not need any other explanation, and he has no time for the speaker's fancies.

The narrator and his neighbor have a disagreement about the importance of mending the wall between their properties.

The narrator thinks that mending the wall every year is silly. They have no livestock to keep in, and his apples don't threaten his neighbor's pine forest. He also feels like something doesn't like the wall, maybe like something in the world is taking it down on purpose, and that's why, when their backs are turned, new cracks appear and the stacked rocks fall back out of place.

The neighbor, on the other hand, stubbornly repeats his father's wisdom: "good fences make good neighbors." He is content to make the yearly trip along the property line in order to ensure that the wall can continue to exist, even if it will always come back down.

The speaker is a person who likes to question tradition and do what seems to make rational sense. Therefore, getting together each year with his neighbor to repair the winter damage to the stone wall that divides their property seems like a waste of time. He notes that neither of them raises livestock, so it makes no sense for them to worry about a wall: livestock from either farm isn't going to wander and do damage. The speaker wishes to give up this laborious wall mending task.

His neighbor, however, has a completely different point of view. His father taught him that good fences make good neighbors, and he sticks with that traditional wisdom in a dogged way. He has no desire to change a custom that goes back many years and seems to serve him well.

The speaker is quite persuasive, though. In fact, he implies his neighbor is living in the stone age:

an old-stone savage armed.
He moves in darkness as it seems to me ...

The neighbor does has some logic on his side. First, the fence repair that the two men engage in together is a bond they share. It is not only the boundary that keeps them good neighbors, but the very idea that "good" fences make good neighbors. Good fences come about by neighbors working together on the project of fence repair and therefore coming into solidarity. Second, there might come a time when there is a need for a fence between the two properties, and if so, one is in place.

Robert Frost's poem "Mending Wall" is a poem that questions traditions. One neighbor is in favor of having a wall between their property simply because it's traditional, whereas the other neighbor sees the needlessness of the wall and how it only serves to separate society.

The first point of view is expressed by the speaker's neighbor who says, not once but twice, "Good fences make good neighbors." In other words, in his view, the only thing in this world that makes a good neighbor is something separating us from our neighbors. Since neighbors offer companionship, he is arguing that the only nice companions in this world are the inanimate objects called fences. Yet, the speaker also notes that the neighbor sees no real reason for having the wall between them except that it is traditional; his father before him had a wall, so he'll have one too.

In contrast, the second point of view is expressed when the speaker notes the needless separation between them that the wall creates, as well as the needless work. The speaker depicts the needless separation when he notes that on certain days during the spring, the two neighbors meet to repair the wall together and "set the wall between us once again." He further depicts the separation the wall creates when he notes, "We keep the wall between us as we go." The speaker also notes the frivolity of the wall by pointing out that the wall is only separating pine trees from an apple orchard, and his apples aren't likely to cross over and eat his neighbor's pine cones. The speaker points out that a wall makes sense when it keeps cows secured on the property, but there are no cows to secure.

By the end of the poem, the reader agrees with the speaker in saying that his neighbor "moves in darkness" that is not caused by just the shade of the woods or other trees. To be in darkness can be seen as another way of saying that someone is unenlightened. In other words, the speaker is asserting that his neighbor is unenlightened by being stuck in the past and holding onto ideas that made sense only in the past.