What is the figurative meaning of the phrase "set the wall between us" in the poem "mending wall"?

I let my neighbor know beyond the hill; 
And on a day we meet to walk the line 
And set the wall between us once again.
We keep the wall between us as we go.

Our speaker has a neighbor.This neighbor lives beyond the hill (we love hills), and, come spring, our speaker tells the neighbor that the wall needs some mending. The two check their calendars, and decide to meet on a day when they’re both free.At this point in time, the two walk the whole length of the wall which separates their properties. Our speaker walks on his side of the wall, and his neighbor walks on the other side of the wall.They fix the wall as they go. Good times.