How to repay the debt of gratitude to your parents?

Your faith guarantees that an infinite number of your ancestors and descendants will attain Buddhahood. Such is the wondrous power of the Mystic Law. How profound and important is your existence! There is also no greater way to repay the debt of gratitude to your parents than through faith.

For Today and Tomorrow
Daily Encouragement by Daisaku Ikeda 20/6

Pure land or hell both lie within one's own heart

Neither the pure land nor hell exists outside ourselves; both lie only within one's own heart. Awakened to this truth, one is called a Buddha; deluded about it, one is called an ordinary person. The Lotus Sutra reveals this truth, and one who embraces the Lotus Sutra will realize that hell is itself the Land of Tranquil Light. 11/7

The Writings of Nichiren Daishonin
Hell is the Land of Tranquil Light
Written to Nanjo Tokimitsu's mother on July 11, 1274

Arouse deep faith, and diligently polish your mirror day and night

A mind now clouded by the illusions of the innate darkness of life is like a tarnished mirror, but when polished, it is sure to become like a clear mirror, reflecting the essential nature of phenomena and the true aspect of reality. Arouse deep faith, and diligently polish your mirror day and night. How should you polish it? Only by chanting Nam-myoho-renge-kyo. 3/3

The Writings of Nichiren Daishonin
On Attaining Buddhahood in this Lifetime
Written to Toki Jonin in 1255