Start with high-confidence inspirational religion books, then narrow by subgenre or adjacent topics.
The Secret of the Golden Flower
Richard Wilhelm, C. G. Jung
The Day Satan Called
Bill Scott
Dear Moon
Zayneb Haleem
The Jeremiah Study Bible, NIV: Jacketed Hardcover
Dr. David Jeremiah, David Jeremiah
The Greatest Thing in the World and Other Addresses
Henry Drummond
The Teachings of Smith Wigglesworth
Smith Wigglesworth
Ascent of Mount Carmel
John of the Cross
The Showings of Divine Love
Julian of Norwich
Showings of Divine Love