It was time for Father John's Saturday night bath, the older nun which normally assisted in this task was a little under the weathers so she instructed Sister Magdalene, a young nun on how to prepare the bath water and towels. Sister Magdalene was also instructed not to look at Father John's nakedness if she could help it, do whatever she's told to do, and pray.
The next morning the old nun asks the sister how the bath had gone. "Oh sister," said the young nun dreamily, "I've been saved!"
"Saved? How did that come about?" asked the old nun.
"Well, when Father John was soaking in the tub, he asked me to wash him. And while I was washing him, he guided my hand down between his legs where he said the lord keeps the key to heaven."
"Did he now--" the old nun said.
Sister Magdalene continued, "And, Father John said that if the key to heaven fit my lock, the portals of heaven would open to me, and I would be assured of salvation and eternal peace. And then Father John guided his key to heaven into my lock."
"Is that a fact?" said the old nun.
"At first it hurt terribly, but Father John said that the pathway to salvation was often painful and that the glory of God would soon swell my heart with ecstasy. And it did, it felt so good being saved."
"That wicked old devil!" said the old nun, "He told me it was Gabriel's Horn, and I've been blowing it these past forty years!"