IN BOOKS, as in life, the Holy Spirit is both omnipresent and invisible. He is the one that blows the apostles out of the Upper Room, and fires their hearts with the courage to speak the gospel. In children’s stories, he is behind that strange human impulse to trust the tiny stock of bravery we possess, and take our chance.

We hardly notice it as we read: of course Jack confronts the giant, and Gretel keeps her head when the witch tries to shove her into the oven. But, given the danger, why don’t they just burst into tears? Because it’s unthinkable. The glory of all the Jacks, Tom Thumbs, Rapunzels, and Goose-girls is that they are ordinary kids, temples of the Holy Spirit, born with a natural love of goodness, and open to the Spirit’s promptings.

Not that they see it like that: they trust to their tiny swords and half-remembered riddles. But it is the deep recesses of the human heart that power these stories — the places where the Spirit dwells. How else can Harry Potter, living as he does in a universe where God is conspicuously absent (J. K. Rowling’s magic world would evaporate at the touch of a real miracle), recognise evil when he sees it — and stand up to it?

One of the greatest moments in The Magic Flute — to step aside into one of the few operas that children enjoy — is the ringing line with which Princess Pamina faces her captor, Sarastro. “What shall we say?” whimpers her companion. “The Truth!” cries Pamina, and the show turns on its axis. Its light-filled conclusion is now assured. Pamina — and Gretel, and all the rest — have called on a greater Spirit than they realise.

Sarah Lenton writes, broadcasts, and lectures on lyric theatre for the Royal Opera House, English National Opera, Glyndebourne Festival Opera, and BBC Radio 3 and 4. She is studying for ordination at St Mellitus College.