We men have one book in common which points to God. Each has it within himself, which is the priceless Name of God. Its letters are the flames of His love, which He out of His heart in the priceless Name of Jesus has revealed in us. Read these letters in your hearts and spirits and you have books enough. All the writings of the children of God direct you unto that one book, for therein lie all the treasures of wisdom. … This book is Christ in you.
Explaining his symbol of the Tetragrammaton within the human heart, in Libri Apologetici (1730), Book I, as quoted in The Secret Teachings of All Ages (1928) by Manly P. Hall, "The Human Body in Symbolism"