We have so many phrases involving digging. Gandhi: "To forget how to dig the earth and tend the soil is to forget ourselves"; Thomas Fuller: "He that plants trees loves others besides himself."
That second one is interesting, because he was one of the earliest poets from the British isles who was able to live by his pen alone.
Indeed, we come from the earth, and return to it when we die. And Gandhi is right—to be truly in touch with ourselves, we must be in touch with our roots, and the earth around us. Put another way, digging is the most basic form of labor.
Heaney's speaker literally speaks in honor of his ancestors, laborously toiling so that he might be able to live by his pen, and makes a bigger statement about how far we've advanced as a species—we now have people like Fuller, like him, who can live on the shoulders of that labor and do a different kind of work: work for the soul.
He adroitly commends his ancestors in the sixth stanza:
Once I carried him milk in a bottle
Corked sloppily with paper. He straightened up
To drink it, then fell to right away
Nicking and slicing neatly, heaving sods
Over his shoulder, digging down and down
For the good turf. Digging.
Milk is a staple drink for Irish farmers, considered a luxurious drink for its nutrition and fat. Notice how his grandfather straightens to drink it, turning away from the earth for luxury—conversely, standing "straight" often connotes pride, or dignity—but then returns to the earth immediately. And he doesn't just turn back to the earth: he falls to it. This is because his grandfather, unlike Heaney himself, does not have the labor of others to stand straight on. He stands only as straight as the shaft of his shovel permits.
Heaney does not do this laborious digging that his father and grandfather do and did. But he does indeed dig. Heaney has the luxury of digging up the complexities of the human condition, the joy of tilling our souls. And Heaney feels both great relief, holding onto his pen "snug as a gun," and great empathy for those who came before him, those people who he literally looks down upon, but speaks of with such great reverence.
He closes by accepting his fate for its advantages and disadvantages, digging his soul for meaning, but afraid he'll never know himself the way his grandfather, who literally tapped into roots, did.
Let's see how a response piece goes...
For Irish Blood
This pen I hold, rolled between finger and thumb,
gnarled like overchewed gum.
Out my screen door, a throaty rasping shout,
a meaty old thunk on the gravelly grout:
My father, coughing. I look out
To see his straining lungs among the tiled porch
Bent low, coming up Forty years away,
A story well-told when he was my age, not so worn by habit,
Where he was living.
His coarsely-haired arm toppling an Italian sailor
Among a raucous crowd of American wine sellers.
Corded bones bulging from his old work—digging—
He arm-wrestled the biggest man in the room and won,
And the crowd went wild.
By God, the old man could tell a story.
And they were all true, he'd remind you.
Just like his old man's.
My grandfather could cut a deck at precisely twenty-six cards,
Count better than any other man at Toner's bar.
Once I brought him a beer, to the pool table
Cap bent from a sloppy pop-off. He straightened up
To drink it, then fell right away to sink the last ball
Elbow rocking steady like a well-oiled knob
Up to his shoulder, going down and down
To wow the crowd watching. Living.
The stale smell of musty beer, the soppy slap
Of soggy cloth, the curt cuts of punches thrown
In the name of love all awaken in my head.
But I've no way to follow men like them.
Between my finger and my thumb
I roll this gnarled pen.
I'll live with it.