Throughout the long history of admiration for the Lotus Sutra, there were many readers and devotees who contributed to its propagation. But only Nichiren devoted his life to reading the Lotus Sutra to such a profound extent, putting both his body and soul into understanding it.
Nichiren suffered numerous religious persecutions which jeopardized even his life. Thanks to these ordeals, however, he gained a deeper understanding of the Lotus Sutra, through which he was able to enter the realm of Buddhist Truth. The life-long experience of religious persecutions is unique to this saint, amounting to special ordeals worse than most ordinary men could endure.
Nichiren himself was aware of this, which is why he said, “Nichiren alone is able to read the words of the Sutra.”
Introduction to the Lotus Sutra