Wall in the poem “Mending the Wall” symbolizes the restrictions between neighbours. Even if you love your neighbour dearly, it is necessary to keep some limits. Otherwise your love will turn into hate.
It is true that there is something in nature that dislikes walls. It makes the frozen ground under the wall expand. Because of this expansion, the wall gets cracks, making the upper stones of the wall fall down to the sides, thus making gaps. This process goes on and the entire wall may crumble if it is not mended in time. By making a wall people want to keep some things in and some things out. The question is “Is it good to have a wall between neighbours?”
The answer seems to be yes. We may not like walls but they are necessary for keeping peace between neighbours. Imagine our neighbour’s goats coming and eating the beautiful plants in our garden. We will denitely not like it. Similarly if our dog catches the chicken of the neighbour will he like it? So walls are needed. Thus wall is symbolic of the restrictions or limitations between neighbours. These limitations are necessary to have permanent and healthy relations.