How did the poet's use of language help to reveal something about relationships in the poem, "Digging" by Seamas Heaney?

"Digging" is a poem about the poet, his father, and his grandfather. The father and grandfather are depicted as men who did manual labor to make a living, whether that was digging turf (the grandfather), or farming potatoes (the father).  Ultimately, however, "Digging" is an exploration of how the poet has, indeed, followed in the footsteps of his grandfather and his father even though the tool he uses is not a shovel. 

The poem opens with a curious metaphor; the poet's pen is like a gun. We know that guns are powerful. How is a pen powerful like a gun? This question rests in the back of the reader's mind as the poet presents memories of his father and grandfather. 

Both of the poet's progenitors are presented as powerful, hard-working men who used shovels in their work. The father apparently learned how to use a spade from his father. Ireland has been, for many people and across generations, a difficult place to make a living. Various historical events and conditions have relegated many to a life of brute labor. One would expect the son, the poet, to be doing the same thing, yet he is with pen in hand, writing about his father digging a flower bed and remembering the years of potato planting. The reader wonders: What are the connections between the older men and the poet? 

The pen in hand, the one that is powerful like a gun, becomes, metaphorically, a spade. This is what the three men have in common. Poetry digs into everyday things to find the deeper meanings in them and deeper connections between them. On the surface it looks as if there are few connections between the older men and the poet, yet when you look past the surface, which Heaney does through metaphor, a pen becomes as powerful as a spade. Language is like a gun; words can cause people to soar and they can send people to deepest despair. When a poet digs deeply, he or she can have a profound influence on others by causing them to rethink the familiar. Implicit to the poem is the poet's apparent hope that he is as good a digger as the men who came before him.