Yes, Gilead by Marilynne Robinson is a clean book.

In 1956, John Ames — a preacher in a small Iowa town, old and ailing — begins a long letter to the young son he won't live to see grow up. What emerges is a life's accounting: his father and his abolitionist grandfather, a friendship that has cost him, and a hard-won gratitude for ordinary light. Winner of the Pulitzer Prize.