More Cardinal Lustiger. "You died for me and I don't give a damn." Huh?

Nova et Vetera has a brief post on Cardinal Lustiger's passing, which recalls an anecdote Cardinal Lustiger used to tell:

I heard a story attributed to him—maybe it is one he told rather than a story about himself (since he himself was a Jewish convert). I was given to understand that the story is a true one.

Two boys were, out of mischief, determined to tease their parish priest, so they went to confession and made up outrageous sins, just to see what the priest would say. The priest, listening to the second boy, realizing that he was being 'had', and hurt by the mockery of the sacrament, asked the second lad as a 'penance' to go to the crucifix over the tabernacle and shout out loud, three times 'you died for me, and I don't give a damn'. The lad did as he was asked; by the third time he was in tears. Some years later, he was ordained a priest.