At the new fruit's core is the tree's starting seed

In a powerful vision, St. Gertrude the Great (d. 1302) was allowed to rest her head near the wound in the Saviour’s breast. As she listened to His beating Heart, she asked St. John, the beloved Apostle, how it was that he, whose head had reposed on the breast of the Savior at the Last Supper, kept complete silence about the throbbing of the adorable Heart of his Master in his writings. She expressed regret to him that he had said nothing about it for our instruction. The saint replied to her:

My mission was to write for the Church, still in its infancy, something about the uncreated Word of God the Father, something which of itself alone would give exercise to every human intellect to the end of time, something that no one would ever succeed in fully understanding. As for the language of these blessed beats of the Heart of Jesus, it is reserved for the last ages when the world, grown old and become cold in the love of God, will need to be warmed again by the revelation of these mysteries. —Legatus divinae pietatis, IV, 305; "Revelationes Gertrudianae", ed. Poitiers and Paris, 1877

From Mark Mallett's The Last Effort