'His Grace the Bishop," said Mr Buckley, my fourth class teacher, "will ask you a question from the catechism." He paused. "And woe betide any boy who doesn't know the answer."
On the day, Mr Buckley accompanied me up the aisle of St Patrick's Church in Monkstown. He seemed as nervous as I was.
Ahead, I saw a robed and mitred figure seated on a throne. This is what is meant, I thought, by a prince of the church. I felt a pressure from Mr Buckley's hand on my shoulder, and I knelt.
The bishop wore a large pectoral cross and held his crozier in his right hand. He extended his left hand to me, and I made to shake it.
Mr Buckley's grip on my shoulder tightened, and I recollected myself. I bowed and kissed the episcopal ring.
"Now, young man," said the bishop, "can you tell me one of the seven gifts you are given by the Holy Spirit at Confirmation?"
My mind went blank. Mr Buckley's knuckles went white. All I could think of was that story by Frank O'Connor about the boy who makes a bags of his first confession.
The other day, some 30 years later, I was sitting in another church, this time as sponsor to my niece, who was making her own Confirmation.
Things had lightened up a lot since Mr Buckley dug his fingers into my shoulder. The oppressive solemnity had given way to a mood of celebration. They didn't even ask you a catechetical question any more.
There wasn't a bishop either; a genial monsignor oversaw proceedings. And he managed to pitch his words in that narrow space in which it's possible to hold the attention of children and adults at the same time.
He was once lucky enough, he said, to be invited to have lunch with the Pope. It was 1980, and he was involved in organising a return visit by Irish young people to Rome after John Paul II's visit here the year before.
The parents in the audience enjoyed the anecdote because it brought them back in time to a prelapsarian Ireland; the children enjoyed it because they learned that the Pope had eggs and rice for lunch.
As it happened, we were in the church of St John the Baptist in Blackrock, the much-cursed church of my boyhood.
It was here that I finally began to understand Einstein's idea that time moves at different speeds in different parts of the universe: it moved very slowly indeed during evening Mass on a Sunday.
In my time, I must have made mental inventories of every aspect of the place: I whiled away countless sermons by counting the panes in the Evie Hone stained-glass window, the statues behind the altar, the stars in Mary's halo, the number of candles lit for special intentions. Sometimes I counted the years since the church was built in 1845 and divided the answer by prime numbers.
Back then, I hated the place and wished the time away. But on this occasion, I felt a fondness for the old church. The impatience of youth always to be somewhere else had faded. I used to glower at the statues and stations of the cross; now they seemed friendly and familiar.
My eyes wandered over the congregation, solid, southside middle-class families, dressed up, but not too much, proud of themselves and their families.
In the old days, I would have found much to ridicule in a celebration of bourgeois values such as this. Now, I felt only the warmth and goodwill that seemed to fill the soaring void of the nave.
It was time to accompany my niece to the altar to be confirmed. I placed an easy hand on her shoulder as we neared the Monsignor. The boy ahead of us announced that he had chosen Diego as his confirmation name, which made everyone smile.
I could tell my niece was nervous, but she coped wonderfully well. She was duly anointed, blessed and confirmed. (She chose the name Lucy).
On the way back to our pew, I remembered what my answer to the bishop had been all those years ago.
"Wisdom," I said.